diff --git a/.oxlintrc.json b/.oxlintrc.json
index dd4578e07..4e16c139b 100644
--- a/.oxlintrc.json
+++ b/.oxlintrc.json
@@ -24,6 +24,17 @@
       "error",
       { "argsIgnorePattern": "^_", "varsIgnorePattern": "^_" }
     ],
-    "@typescript-eslint/no-explicit-any": "warn"
+    "@typescript-eslint/no-explicit-any": "warn",
+    "no-restricted-imports": [
+      "error",
+      {
+        "patterns": [
+          {
+            "regex": "^\\$lib(/|$)",
+            "message": "SvelteKit 3 removes $lib. Use #lib with an explicit extension (e.g. #lib/types/task.js)."
+          }
+        ]
+      }
+    ]
   }
 }
diff --git a/docs/guides/agent-rules/prisma-db.md b/docs/guides/agent-rules/prisma-db.md
index 1a0b3891f..a405e9e82 100644
--- a/docs/guides/agent-rules/prisma-db.md
+++ b/docs/guides/agent-rules/prisma-db.md
@@ -21,7 +21,7 @@ paths:
 
 ## Server-Only Code
 
-- Import the DB client (`$lib/server/database`) only in `src/lib/server/**` and in server-only services under `src/lib/services/**` and `src/features/**/services/**`
+- Import the DB client (`#lib/server/database.js`) only in `src/lib/server/**` and in server-only services under `src/lib/services/**` and `src/features/**/services/**`
 - Never import server-only code in client components
 
 ## Service Layer
diff --git a/docs/guides/agent-rules/server-cache.md b/docs/guides/agent-rules/server-cache.md
index f52599379..b8231faf2 100644
--- a/docs/guides/agent-rules/server-cache.md
+++ b/docs/guides/agent-rules/server-cache.md
@@ -78,7 +78,7 @@ Services call `getCached*()` with a `fetchFn` that performs the DB query. The se
 
 ```typescript
 // In service file
-import { getCachedTasksMap } from '$lib/server/tasks/cache';
+import { getCachedTasksMap } from '#lib/server/tasks/cache.js';
 
 export async function getTasksByTaskId(): Promise<Map<string, Task>> {
   return getCachedTasksMap(async () => {
@@ -91,7 +91,7 @@ export async function getTasksByTaskId(): Promise<Map<string, Task>> {
 Mock cache in service tests to bypass caching:
 
 ```typescript
-vi.mock('$lib/server/tasks/cache', () => ({
+vi.mock('#lib/server/tasks/cache.js', () => ({
   getCachedTasksMap: (fetchFn: () => Promise<unknown>) => fetchFn(),
   invalidateTaskCaches: vi.fn(),
 }));
diff --git a/docs/guides/agent-rules/testing-e2e.md b/docs/guides/agent-rules/testing-e2e.md
index f61df69eb..1c38e55ae 100644
--- a/docs/guides/agent-rules/testing-e2e.md
+++ b/docs/guides/agent-rules/testing-e2e.md
@@ -10,7 +10,7 @@ paths:
 ## Setup
 
 - File extension: **must** be `.spec.ts` (`.test.ts` not detected by `playwright.config.ts`)
-- No path aliases (`$lib`, `$features` not resolved outside SvelteKit). Use type-only imports for types:
+- No path aliases or subpath imports (`$features` is resolved only by Vite; `#lib/*.js` resolves to `src/lib/*.js`, but the Playwright runner does not map it to the `.ts` source). Use type-only imports for types:
 
 ```typescript
 // Bad: runtime import fails in E2E
diff --git a/docs/guides/agent-rules/testing.md b/docs/guides/agent-rules/testing.md
index f26d0f821..6d3e8f446 100644
--- a/docs/guides/agent-rules/testing.md
+++ b/docs/guides/agent-rules/testing.md
@@ -70,7 +70,7 @@ test.each([TaskGrade.PENDING, TaskGrade.Q11, TaskGrade.Q10, TaskGrade.D6])(
 
 ### Service Layer (Prisma)
 
-Mock with `vi.mock('$lib/server/database', ...)`. Use helpers:
+Mock with `vi.mock('#lib/server/database.js', ...)`. Use helpers:
 
 ```typescript
 const mockFindUnique = (data) => db.task.findUnique.mockResolvedValue(data);
@@ -95,7 +95,7 @@ afterAll(() => disposeDomainCaches());
 beforeEach(() => invalidateDomainCaches());
 
 // Bypass caching in service tests:
-vi.mock('$lib/server/tasks/cache', () => ({
+vi.mock('#lib/server/tasks/cache.js', () => ({
   getCachedTasksMap: (fetchFn: () => Promise<unknown>) => fetchFn(),
   invalidateTaskCaches: vi.fn(),
 }));
diff --git a/docs/guides/architecture.md b/docs/guides/architecture.md
index eb652fa4f..9f35fb9b5 100644
--- a/docs/guides/architecture.md
+++ b/docs/guides/architecture.md
@@ -75,7 +75,7 @@ feature 内は技術的な役割で分ける。必要なディレクトリだけ
 - `utils/`: 副作用のない関数。テストを隣接配置する。
 - `stores/`: Svelte Runes を使う `.svelte.ts`。
 
-`features/{feature}/server/` は `$lib/server/` と違い、SvelteKit が client import を自動では禁止しない。規約と推移的な server-only dependency により client から分離する。複数 feature で使うサーバコードは `src/lib/server/` へ移す。
+`features/{feature}/server/` は `src/lib/server/` と違い、SvelteKit が client import を自動では禁止しない。規約と推移的な server-only dependency により client から分離する。複数 feature で使うサーバコードは `src/lib/server/` へ移す。
 
 ### 3. src/lib
 
@@ -139,12 +139,15 @@ include: [
 ];
 ```
 
-### 6. path alias
+### 6. path alias と subpath imports
 
-`svelte.config.js` で `$lib` と `$features` を定義している。
+`src/lib` は `package.json#imports` の `#lib/*` で参照する。SvelteKit 3 で組み込みの `$lib` が削除されるため `$lib` は使わず、oxlint と ESLint の `no-restricted-imports` で禁止している。
+`#lib` には明示的な拡張子が必要で、TS モジュールは `.js`、コンポーネントは `.svelte`、runes モジュール（`.svelte.ts`）は `.svelte.js` と書く。`vi.mock` の specifier も同じ形にする。
+lint が検出するのは import・export 宣言（`import type`・`export … from` を含む）と `.ts` の動的 `import()` で、`vi.mock('$lib/...')` と `.svelte` 内の動的 `import()` は検出しない。import の specifier をまとめて変えたときは、`rg -n '\$lib' src e2e prisma` で残りが無いことも確かめる。
+`$features` は `svelte.config.js` の alias で定義している。
 
 ```typescript
-import { formatDate } from '$lib/utils/format';
+import { formatDate } from '#lib/utils/format.js';
 import WorkBookForm from '$features/workbooks/components/shared/WorkBookForm.svelte';
 import type { PageServerLoad } from './$types';
 ```
diff --git a/eslint.config.mjs b/eslint.config.mjs
index 4adef090a..cd19da504 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -80,6 +80,19 @@ export default [
       'svelte/no-useless-mustaches': 'warn',
       'svelte/prefer-writable-derived': 'warn', // New in 3.6.0 - prefer $derived over $state+$effect
       'svelte/valid-prop-names-in-kit-pages': 'warn', // Allow props other than data/errors in pages
+      // Kit 2 still resolves $lib, so new imports would only break on Kit 3; oxlint covers JS/TS files
+      'no-restricted-imports': [
+        'error',
+        {
+          patterns: [
+            {
+              regex: '^\\$lib(/|$)',
+              message:
+                'SvelteKit 3 removes $lib. Use #lib with an explicit extension (e.g. #lib/types/task.js).',
+            },
+          ],
+        },
+      ],
       'no-unused-vars': 'off', // Use TypeScript version instead
       'no-undef': 'off', // TypeScript handles this
     },
diff --git a/package.json b/package.json
index 0c796a087..d16d1b94c 100644
--- a/package.json
+++ b/package.json
@@ -70,6 +70,9 @@
     "zod": "4.6.7"
   },
   "type": "module",
+  "imports": {
+    "#lib/*": "./src/lib/*"
+  },
   "dependencies": {
     "@dnd-kit/helpers": "0.5.1",
     "@dnd-kit/svelte": "0.5.1",
diff --git a/src/features/account/components/delete/AccountDeletionForm.svelte b/src/features/account/components/delete/AccountDeletionForm.svelte
index c41ea0deb..8cccb6398 100644
--- a/src/features/account/components/delete/AccountDeletionForm.svelte
+++ b/src/features/account/components/delete/AccountDeletionForm.svelte
@@ -2,9 +2,9 @@
   import { Input, Button, Alert, Checkbox, Modal } from 'flowbite-svelte';
   import Info from '@lucide/svelte/icons/info';
 
-  import ContainerWrapper from '$lib/components/ContainerWrapper.svelte';
-  import FormWrapper from '$lib/components/FormWrapper.svelte';
-  import LabelWrapper from '$lib/components/LabelWrapper.svelte';
+  import ContainerWrapper from '#lib/components/ContainerWrapper.svelte';
+  import FormWrapper from '#lib/components/FormWrapper.svelte';
+  import LabelWrapper from '#lib/components/LabelWrapper.svelte';
   import WarningMessageOnDeletingAccount from './WarningMessageOnDeletingAccount.svelte';
 
   interface Props {
diff --git a/src/features/account/components/settings/AtCoderVerificationForm.svelte b/src/features/account/components/settings/AtCoderVerificationForm.svelte
index 506cb4b28..047d8aafd 100644
--- a/src/features/account/components/settings/AtCoderVerificationForm.svelte
+++ b/src/features/account/components/settings/AtCoderVerificationForm.svelte
@@ -3,10 +3,10 @@
   import { Label, Input, P, Clipboard } from 'flowbite-svelte';
   import ClipboardCopy from '@lucide/svelte/icons/clipboard-copy';
   import Check from '@lucide/svelte/icons/check';
-  import ContainerWrapper from '$lib/components/ContainerWrapper.svelte';
-  import FormWrapper from '$lib/components/FormWrapper.svelte';
-  import LabelWrapper from '$lib/components/LabelWrapper.svelte';
-  import SubmissionButton from '$lib/components/SubmissionButton.svelte';
+  import ContainerWrapper from '#lib/components/ContainerWrapper.svelte';
+  import FormWrapper from '#lib/components/FormWrapper.svelte';
+  import LabelWrapper from '#lib/components/LabelWrapper.svelte';
+  import SubmissionButton from '#lib/components/SubmissionButton.svelte';
 
   interface Props {
     username: string;
diff --git a/src/features/account/services/atcoder_verification.test.ts b/src/features/account/services/atcoder_verification.test.ts
index a758a7b34..16fa2b32b 100644
--- a/src/features/account/services/atcoder_verification.test.ts
+++ b/src/features/account/services/atcoder_verification.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect, vi, beforeEach, afterEach } from 'vitest';
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     user: {
       findUniqueOrThrow: vi.fn(),
@@ -13,13 +13,13 @@ vi.mock('$lib/server/database', () => ({
   },
 }));
 
-vi.mock('$lib/utils/hash', () => ({
+vi.mock('#lib/utils/hash.js', () => ({
   sha256: vi.fn().mockResolvedValue('mocked-hash'),
 }));
 
 import { Roles, type AtCoderAccount } from '@prisma/client';
 
-import prisma from '$lib/server/database';
+import prisma from '#lib/server/database.js';
 import { generate, validate, reset } from './atcoder_verification';
 
 // ---------------------------------------------------------------------------
diff --git a/src/features/account/services/atcoder_verification.ts b/src/features/account/services/atcoder_verification.ts
index 2fa856076..37878bc65 100644
--- a/src/features/account/services/atcoder_verification.ts
+++ b/src/features/account/services/atcoder_verification.ts
@@ -1,5 +1,5 @@
-import { default as db } from '$lib/server/database';
-import { sha256 } from '$lib/utils/hash';
+import { default as db } from '#lib/server/database.js';
+import { sha256 } from '#lib/utils/hash.js';
 
 const EXTERNAL_API_TIMEOUT_MS = 5000;
 
diff --git a/src/features/auth/server/session.test.ts b/src/features/auth/server/session.test.ts
index f67ae1211..cfcc1ce5b 100644
--- a/src/features/auth/server/session.test.ts
+++ b/src/features/auth/server/session.test.ts
@@ -2,7 +2,7 @@ import { describe, test, expect, beforeEach, afterEach, vi } from 'vitest';
 
 import { Prisma, Roles } from '@prisma/client';
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     session: {
       create: vi.fn(),
@@ -13,7 +13,7 @@ vi.mock('$lib/server/database', () => ({
   },
 }));
 
-import db from '$lib/server/database';
+import db from '#lib/server/database.js';
 import { createSession, validateSession, invalidateSession, SESSION_COOKIE_NAME } from './session';
 
 const mockDb = db as unknown as {
diff --git a/src/features/auth/server/session.ts b/src/features/auth/server/session.ts
index 00eeb952f..a687c29af 100644
--- a/src/features/auth/server/session.ts
+++ b/src/features/auth/server/session.ts
@@ -1,7 +1,7 @@
 import { PrismaClientKnownRequestError } from '@prisma/client/runtime/library';
 import type { Roles } from '@prisma/client';
 
-import client from '$lib/server/database';
+import client from '#lib/server/database.js';
 import { generateRandomString } from './random';
 
 // lucia v2 defaults: active 24h, idle +14d
diff --git a/src/features/auth/services/admin_access.test.ts b/src/features/auth/services/admin_access.test.ts
index c10a26b88..b6667ca06 100644
--- a/src/features/auth/services/admin_access.test.ts
+++ b/src/features/auth/services/admin_access.test.ts
@@ -19,12 +19,12 @@ vi.mock('@sveltejs/kit', () => {
   return { redirect: vi.fn(redirectImpl), error: vi.fn(errorImpl) };
 });
 
-vi.mock('$lib/services/users', () => ({
+vi.mock('#lib/services/users.js', () => ({
   getUser: vi.fn(),
 }));
 
-import * as userService from '$lib/services/users';
-import { Roles } from '$lib/types/user';
+import * as userService from '#lib/services/users.js';
+import { Roles } from '#lib/types/user.js';
 import { validateAdminAccess, validateAdminAccessForApi } from './admin_access';
 
 const createMockLocalsWithSession = (username = 'admin-user') =>
diff --git a/src/features/auth/services/admin_access.ts b/src/features/auth/services/admin_access.ts
index 7850b6d22..64bce1258 100644
--- a/src/features/auth/services/admin_access.ts
+++ b/src/features/auth/services/admin_access.ts
@@ -1,15 +1,15 @@
 import { redirect, error } from '@sveltejs/kit';
 
-import * as userService from '$lib/services/users';
+import * as userService from '#lib/services/users.js';
 
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 
-import { isAdmin } from '$lib/utils/authorship';
+import { isAdmin } from '#lib/utils/authorship.js';
 import {
   TEMPORARY_REDIRECT,
   UNAUTHORIZED,
   FORBIDDEN,
-} from '$lib/constants/http-response-status-codes';
+} from '#lib/constants/http-response-status-codes.js';
 
 import { buildLoginPath } from '../utils/login';
 
diff --git a/src/features/auth/services/credentials.test.ts b/src/features/auth/services/credentials.test.ts
index 4988afa96..7b84c47d0 100644
--- a/src/features/auth/services/credentials.test.ts
+++ b/src/features/auth/services/credentials.test.ts
@@ -2,7 +2,7 @@ import { describe, test, expect, vi } from 'vitest';
 
 import { Prisma } from '@prisma/client';
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     $transaction: vi.fn(),
     user: {
@@ -20,7 +20,7 @@ vi.mock('../server/password', () => ({
   verifyPassword: vi.fn(),
 }));
 
-import db from '$lib/server/database';
+import db from '#lib/server/database.js';
 import { hashPassword, verifyPassword } from '../server/password';
 import { registerUser, authenticateUser } from './credentials';
 
diff --git a/src/features/auth/services/credentials.ts b/src/features/auth/services/credentials.ts
index 4d1022e1c..b1eb6dc5f 100644
--- a/src/features/auth/services/credentials.ts
+++ b/src/features/auth/services/credentials.ts
@@ -1,6 +1,6 @@
 import { PrismaClientKnownRequestError } from '@prisma/client/runtime/library';
 
-import client from '$lib/server/database';
+import client from '#lib/server/database.js';
 import { hashPassword, verifyPassword } from '../server/password';
 import { generateRandomString } from '../server/random';
 
diff --git a/src/features/auth/services/session_guards.ts b/src/features/auth/services/session_guards.ts
index 4eb97bf92..9a1be260f 100644
--- a/src/features/auth/services/session_guards.ts
+++ b/src/features/auth/services/session_guards.ts
@@ -1,6 +1,6 @@
 import { redirect } from '@sveltejs/kit';
 
-import { TEMPORARY_REDIRECT } from '$lib/constants/http-response-status-codes';
+import { TEMPORARY_REDIRECT } from '#lib/constants/http-response-status-codes.js';
 
 import { buildLoginPath } from '../utils/login';
 
diff --git a/src/features/auth/utils/login.ts b/src/features/auth/utils/login.ts
index 192840e32..d29d273ef 100644
--- a/src/features/auth/utils/login.ts
+++ b/src/features/auth/utils/login.ts
@@ -1,4 +1,4 @@
-import { LOGIN_PAGE } from '$lib/constants/navbar-links';
+import { LOGIN_PAGE } from '#lib/constants/navbar-links.js';
 
 /**
  * Builds the login path with an optional redirect parameter.
diff --git a/src/features/auth/utils/signup.ts b/src/features/auth/utils/signup.ts
index 2f83dc5ae..6a8bcb1a1 100644
--- a/src/features/auth/utils/signup.ts
+++ b/src/features/auth/utils/signup.ts
@@ -1,4 +1,4 @@
-import { SIGNUP_PAGE } from '$lib/constants/navbar-links';
+import { SIGNUP_PAGE } from '#lib/constants/navbar-links.js';
 
 /**
  * Builds the signup path with an optional redirect parameter.
diff --git a/src/features/tasks/components/contest-table/TaskTable.svelte b/src/features/tasks/components/contest-table/TaskTable.svelte
index a89ee2ed4..ab635fa87 100644
--- a/src/features/tasks/components/contest-table/TaskTable.svelte
+++ b/src/features/tasks/components/contest-table/TaskTable.svelte
@@ -13,13 +13,13 @@
     TableHeadCell,
   } from 'flowbite-svelte';
 
-  import type { TaskResults, TaskResult } from '$lib/types/task';
+  import type { TaskResults, TaskResult } from '#lib/types/task.js';
   import type {
     ContestTableProvider,
     ContestTableDisplayConfig,
     ContestTableMetaData,
   } from '$features/tasks/types/contest-table/contest_table_provider';
-  import type { ContestTaskPairKey } from '$lib/types/contest_task_pair';
+  import type { ContestTaskPairKey } from '#lib/types/contest_task_pair.js';
   import type { VoteStatisticsMap } from '$features/votes/types/vote_result';
 
   import TaskTableBodyCell from './TaskTableBodyCell.svelte';
@@ -31,11 +31,11 @@
     type ContestTableProviderGroups,
   } from '$features/tasks/utils/contest-table/contest_table_provider';
 
-  import { useLocalStorage } from '$lib/stores/local_storage_helper.svelte';
+  import { useLocalStorage } from '#lib/stores/local_storage_helper.svelte.js';
 
-  import { getBackgroundColorFrom } from '$lib/services/submission_status';
-  import { areAllTasksAccepted } from '$lib/utils/task';
-  import { createContestTaskPairKey } from '$lib/utils/contest_task_pair';
+  import { getBackgroundColorFrom } from '#lib/services/submission_status.js';
+  import { areAllTasksAccepted } from '#lib/utils/task.js';
+  import { createContestTaskPairKey } from '#lib/utils/contest_task_pair.js';
   import { getBodyRowClasses } from './_utils/contest_table_layout';
 
   interface Props {
diff --git a/src/features/tasks/components/contest-table/TaskTableBodyCell.svelte b/src/features/tasks/components/contest-table/TaskTableBodyCell.svelte
index 568b21330..47197ed3d 100644
--- a/src/features/tasks/components/contest-table/TaskTableBodyCell.svelte
+++ b/src/features/tasks/components/contest-table/TaskTableBodyCell.svelte
@@ -1,12 +1,12 @@
 <script lang="ts">
-  import type { TaskResult } from '$lib/types/task';
+  import type { TaskResult } from '#lib/types/task.js';
   import type { VoteStatisticsMap } from '$features/votes/types/vote_result';
 
   import VotableGrade from '@/features/votes/components/VotableGrade.svelte';
-  import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
-  import UpdatingDropdown from '$lib/components/SubmissionStatus/UpdatingDropdown.svelte';
+  import ExternalLinkWrapper from '#lib/components/ExternalLinkWrapper.svelte';
+  import UpdatingDropdown from '#lib/components/SubmissionStatus/UpdatingDropdown.svelte';
 
-  import { getTaskUrl, removeTaskIndexFromTitle } from '$lib/utils/task';
+  import { getTaskUrl, removeTaskIndexFromTitle } from '#lib/utils/task.js';
   import { formatAojTitle } from '$features/tasks/utils/contest-table/aoj_labels';
 
   interface Props {
diff --git a/src/features/tasks/fixtures/contest-table/contest_table_provider.ts b/src/features/tasks/fixtures/contest-table/contest_table_provider.ts
index 9bc94ef7c..d8756e1ab 100644
--- a/src/features/tasks/fixtures/contest-table/contest_table_provider.ts
+++ b/src/features/tasks/fixtures/contest-table/contest_table_provider.ts
@@ -1,4 +1,4 @@
-import { TaskGrade, type TaskResult, type TaskResults } from '$lib/types/task';
+import { TaskGrade, type TaskResult, type TaskResults } from '#lib/types/task.js';
 
 // Default task result with minimal initialization.
 // Most fields are empty strings as they're not relevant for these tests.
diff --git a/src/features/tasks/stores/active_contest_type.svelte.ts b/src/features/tasks/stores/active_contest_type.svelte.ts
index cfebdf254..95f1a75f6 100644
--- a/src/features/tasks/stores/active_contest_type.svelte.ts
+++ b/src/features/tasks/stores/active_contest_type.svelte.ts
@@ -1,4 +1,4 @@
-import { useLocalStorage } from '$lib/stores/local_storage_helper.svelte';
+import { useLocalStorage } from '#lib/stores/local_storage_helper.svelte.js';
 import {
   type ContestTableProviderGroups,
   contestTableProviderGroups,
diff --git a/src/features/tasks/types/contest-table/contest_table_provider.ts b/src/features/tasks/types/contest-table/contest_table_provider.ts
index 83cc676e7..7facf3e99 100644
--- a/src/features/tasks/types/contest-table/contest_table_provider.ts
+++ b/src/features/tasks/types/contest-table/contest_table_provider.ts
@@ -1,5 +1,5 @@
-import type { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults, TaskResult } from '$lib/types/task';
+import type { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults, TaskResult } from '#lib/types/task.js';
 
 /**
  * Provider interface for building and managing contest tables.
diff --git a/src/features/tasks/utils/contest-table/aalc_provider.test.ts b/src/features/tasks/utils/contest-table/aalc_provider.test.ts
index b89fd0200..1f27aa698 100644
--- a/src/features/tasks/utils/contest-table/aalc_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/aalc_provider.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { AALCProvider } from './aalc_provider';
 
diff --git a/src/features/tasks/utils/contest-table/aalc_provider.ts b/src/features/tasks/utils/contest-table/aalc_provider.ts
index 29dc72046..77fc6d6cd 100644
--- a/src/features/tasks/utils/contest-table/aalc_provider.ts
+++ b/src/features/tasks/utils/contest-table/aalc_provider.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/abc_providers.test.ts b/src/features/tasks/utils/contest-table/abc_providers.test.ts
index 651e00df5..42834bc2d 100644
--- a/src/features/tasks/utils/contest-table/abc_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/abc_providers.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResult, TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResult, TaskResults } from '#lib/types/task.js';
 
 import {
   ABC319OnwardsProvider,
diff --git a/src/features/tasks/utils/contest-table/abc_providers.ts b/src/features/tasks/utils/contest-table/abc_providers.ts
index 84b68538f..9cac83b2d 100644
--- a/src/features/tasks/utils/contest-table/abc_providers.ts
+++ b/src/features/tasks/utils/contest-table/abc_providers.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests';
+import { classifyContest, getContestNameLabel } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/abs_provider.test.ts b/src/features/tasks/utils/contest-table/abs_provider.test.ts
index 54def4c19..9e196dec4 100644
--- a/src/features/tasks/utils/contest-table/abs_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/abs_provider.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { ABSProvider } from './abs_provider';
 import { taskResultsForABS } from '$features/tasks/fixtures/contest-table/contest_table_provider';
diff --git a/src/features/tasks/utils/contest-table/abs_provider.ts b/src/features/tasks/utils/contest-table/abs_provider.ts
index 8d27f2a1f..5028956da 100644
--- a/src/features/tasks/utils/contest-table/abs_provider.ts
+++ b/src/features/tasks/utils/contest-table/abs_provider.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/acl_providers.test.ts b/src/features/tasks/utils/contest-table/acl_providers.test.ts
index c2c4b4826..4efb0845d 100644
--- a/src/features/tasks/utils/contest-table/acl_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/acl_providers.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { ACLPracticeProvider, ACLBeginnerProvider, ACLProvider } from './acl_providers';
 import {
diff --git a/src/features/tasks/utils/contest-table/acl_providers.ts b/src/features/tasks/utils/contest-table/acl_providers.ts
index e369eb9c7..8179d0197 100644
--- a/src/features/tasks/utils/contest-table/acl_providers.ts
+++ b/src/features/tasks/utils/contest-table/acl_providers.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/agc_provider.test.ts b/src/features/tasks/utils/contest-table/agc_provider.test.ts
index c11600c68..d3e1f82a8 100644
--- a/src/features/tasks/utils/contest-table/agc_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/agc_provider.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { AGC001OnwardsProvider } from './agc_provider';
 import { parseContestRound } from './contest_table_provider_base';
diff --git a/src/features/tasks/utils/contest-table/agc_provider.ts b/src/features/tasks/utils/contest-table/agc_provider.ts
index 560a8fa49..318768476 100644
--- a/src/features/tasks/utils/contest-table/agc_provider.ts
+++ b/src/features/tasks/utils/contest-table/agc_provider.ts
@@ -1,7 +1,7 @@
 import { type ContestTableMetaData } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests';
+import { classifyContest, getContestNameLabel } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/aoj_icpc_providers.test.ts b/src/features/tasks/utils/contest-table/aoj_icpc_providers.test.ts
index 046db0b88..7da77a820 100644
--- a/src/features/tasks/utils/contest-table/aoj_icpc_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/aoj_icpc_providers.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect, beforeEach, afterEach } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { AOJ_LABEL_OVERRIDES } from './aoj_labels';
 import { AojIcpcPrelimProvider, AojIcpcRegionalProvider } from './aoj_icpc_providers';
diff --git a/src/features/tasks/utils/contest-table/aoj_icpc_providers.ts b/src/features/tasks/utils/contest-table/aoj_icpc_providers.ts
index 92df296e4..cda8b32a6 100644
--- a/src/features/tasks/utils/contest-table/aoj_icpc_providers.ts
+++ b/src/features/tasks/utils/contest-table/aoj_icpc_providers.ts
@@ -1,5 +1,5 @@
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResult, TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResult, TaskResults } from '#lib/types/task.js';
 import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
diff --git a/src/features/tasks/utils/contest-table/aoj_jag_providers.test.ts b/src/features/tasks/utils/contest-table/aoj_jag_providers.test.ts
index 5828d6025..e8b2f6fcd 100644
--- a/src/features/tasks/utils/contest-table/aoj_jag_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/aoj_jag_providers.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { JagPrelimProvider } from './aoj_jag_providers';
 
diff --git a/src/features/tasks/utils/contest-table/aoj_jag_providers.ts b/src/features/tasks/utils/contest-table/aoj_jag_providers.ts
index e004f7193..7f0aa5e73 100644
--- a/src/features/tasks/utils/contest-table/aoj_jag_providers.ts
+++ b/src/features/tasks/utils/contest-table/aoj_jag_providers.ts
@@ -1,5 +1,5 @@
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResult, TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResult, TaskResults } from '#lib/types/task.js';
 import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
diff --git a/src/features/tasks/utils/contest-table/aoj_labels.test.ts b/src/features/tasks/utils/contest-table/aoj_labels.test.ts
index c457be18a..a0719fafd 100644
--- a/src/features/tasks/utils/contest-table/aoj_labels.test.ts
+++ b/src/features/tasks/utils/contest-table/aoj_labels.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect, beforeEach, afterEach } from 'vitest';
 
-import type { TaskResults } from '$lib/types/task';
+import type { TaskResults } from '#lib/types/task.js';
 
 import {
   buildAojLetterMap,
diff --git a/src/features/tasks/utils/contest-table/aoj_labels.ts b/src/features/tasks/utils/contest-table/aoj_labels.ts
index 6e67a813d..7e28bd0b2 100644
--- a/src/features/tasks/utils/contest-table/aoj_labels.ts
+++ b/src/features/tasks/utils/contest-table/aoj_labels.ts
@@ -1,4 +1,4 @@
-import type { TaskResults } from '$lib/types/task';
+import type { TaskResults } from '#lib/types/task.js';
 import type {
   ContestTableDisplayConfig,
   ContestTableTitleStyle,
diff --git a/src/features/tasks/utils/contest-table/arc_providers.test.ts b/src/features/tasks/utils/contest-table/arc_providers.test.ts
index 4acb3938e..3c42c148b 100644
--- a/src/features/tasks/utils/contest-table/arc_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/arc_providers.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResult, TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResult, TaskResults } from '#lib/types/task.js';
 
 import {
   ARC104OnwardsProvider,
diff --git a/src/features/tasks/utils/contest-table/arc_providers.ts b/src/features/tasks/utils/contest-table/arc_providers.ts
index 070dc1e01..c3c613716 100644
--- a/src/features/tasks/utils/contest-table/arc_providers.ts
+++ b/src/features/tasks/utils/contest-table/arc_providers.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests';
+import { classifyContest, getContestNameLabel } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/awc_provider.test.ts b/src/features/tasks/utils/contest-table/awc_provider.test.ts
index 99bd4e4b8..8415752e5 100644
--- a/src/features/tasks/utils/contest-table/awc_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/awc_provider.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { AWCRangeProvider, AWCSpecialContestProvider } from './awc_provider';
 import {
diff --git a/src/features/tasks/utils/contest-table/awc_provider.ts b/src/features/tasks/utils/contest-table/awc_provider.ts
index ad690d1fd..39c554b4d 100644
--- a/src/features/tasks/utils/contest-table/awc_provider.ts
+++ b/src/features/tasks/utils/contest-table/awc_provider.ts
@@ -2,10 +2,10 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResult } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests';
+import { classifyContest, getContestNameLabel } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/axc_like_provider.test.ts b/src/features/tasks/utils/contest-table/axc_like_provider.test.ts
index 3fba7b855..999a1c9af 100644
--- a/src/features/tasks/utils/contest-table/axc_like_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/axc_like_provider.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { ABCLikeProvider } from './axc_like_provider';
 import { taskResultsForABCLikeProvider } from '$features/tasks/fixtures/contest-table/contest_table_provider';
diff --git a/src/features/tasks/utils/contest-table/axc_like_provider.ts b/src/features/tasks/utils/contest-table/axc_like_provider.ts
index d70865ff9..488764d23 100644
--- a/src/features/tasks/utils/contest-table/axc_like_provider.ts
+++ b/src/features/tasks/utils/contest-table/axc_like_provider.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_base.test.ts b/src/features/tasks/utils/contest-table/contest_table_provider_base.test.ts
index 5dbdb797d..a2c407175 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_base.test.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_base.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 
 import { ABSProvider } from './contest_table_provider';
 import { taskResultsForABS } from '$features/tasks/fixtures/contest-table/contest_table_provider';
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_base.ts b/src/features/tasks/utils/contest-table/contest_table_provider_base.ts
index fb36f1545..7adf4a769 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_base.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_base.ts
@@ -5,10 +5,10 @@ import {
   type ContestTableDisplayConfig,
   type ProviderKey,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults, TaskResult } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults, TaskResult } from '#lib/types/task.js';
 
-import { getTaskTableHeaderName } from '$lib/utils/task';
+import { getTaskTableHeaderName } from '#lib/utils/task.js';
 
 export abstract class ContestTableProviderBase implements ContestTableProvider {
   protected readonly contestType: ContestType;
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_group.test.ts b/src/features/tasks/utils/contest-table/contest_table_provider_group.test.ts
index ac7aaeded..9d48662b3 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_group.test.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_group.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 
 import {
   ABSProvider,
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_group.ts b/src/features/tasks/utils/contest-table/contest_table_provider_group.ts
index 781b812bf..3b8cc32e2 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_group.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_group.ts
@@ -1,5 +1,5 @@
 import { type ContestTablesMetaData } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_groups.test.ts b/src/features/tasks/utils/contest-table/contest_table_provider_groups.test.ts
index fd503cce1..c1c6e70c3 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_groups.test.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_groups.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 
 import { TESSOKU_SECTIONS } from '$features/tasks/types/contest-table/contest_table_provider';
 
diff --git a/src/features/tasks/utils/contest-table/contest_table_provider_groups.ts b/src/features/tasks/utils/contest-table/contest_table_provider_groups.ts
index cd5478b23..1e8d772ae 100644
--- a/src/features/tasks/utils/contest-table/contest_table_provider_groups.ts
+++ b/src/features/tasks/utils/contest-table/contest_table_provider_groups.ts
@@ -1,4 +1,4 @@
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 
 import { ABSProvider } from './abs_provider';
 import {
diff --git a/src/features/tasks/utils/contest-table/dp_providers.test.ts b/src/features/tasks/utils/contest-table/dp_providers.test.ts
index c88cd189c..64eb5ab1a 100644
--- a/src/features/tasks/utils/contest-table/dp_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/dp_providers.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { EDPCProvider, TDPCProvider, NDPCProvider } from './dp_providers';
 
diff --git a/src/features/tasks/utils/contest-table/dp_providers.ts b/src/features/tasks/utils/contest-table/dp_providers.ts
index bec79d884..a74b2b0a8 100644
--- a/src/features/tasks/utils/contest-table/dp_providers.ts
+++ b/src/features/tasks/utils/contest-table/dp_providers.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/fps24_provider.test.ts b/src/features/tasks/utils/contest-table/fps24_provider.test.ts
index a520a86ae..866e523e8 100644
--- a/src/features/tasks/utils/contest-table/fps24_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/fps24_provider.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { FPS24Provider } from './fps24_provider';
 
diff --git a/src/features/tasks/utils/contest-table/fps24_provider.ts b/src/features/tasks/utils/contest-table/fps24_provider.ts
index 6fd2e8eb6..0234d0b8c 100644
--- a/src/features/tasks/utils/contest-table/fps24_provider.ts
+++ b/src/features/tasks/utils/contest-table/fps24_provider.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/game24_provider.test.ts b/src/features/tasks/utils/contest-table/game24_provider.test.ts
index d45805754..c57137fb9 100644
--- a/src/features/tasks/utils/contest-table/game24_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/game24_provider.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { Game24Provider } from './game24_provider';
 
diff --git a/src/features/tasks/utils/contest-table/game24_provider.ts b/src/features/tasks/utils/contest-table/game24_provider.ts
index 8d8060650..18a5451a1 100644
--- a/src/features/tasks/utils/contest-table/game24_provider.ts
+++ b/src/features/tasks/utils/contest-table/game24_provider.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/joi_providers.test.ts b/src/features/tasks/utils/contest-table/joi_providers.test.ts
index ce586939f..cf362a8ea 100644
--- a/src/features/tasks/utils/contest-table/joi_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/joi_providers.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import {
   JOIFirstQualRoundProvider,
diff --git a/src/features/tasks/utils/contest-table/joi_providers.ts b/src/features/tasks/utils/contest-table/joi_providers.ts
index eb9abd041..b1f68475b 100644
--- a/src/features/tasks/utils/contest-table/joi_providers.ts
+++ b/src/features/tasks/utils/contest-table/joi_providers.ts
@@ -4,10 +4,10 @@ import {
   JOI_SECOND_QUAL_ROUND_SECTIONS,
   JOI_FINAL_ROUND_SECTIONS,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResult } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests';
+import { classifyContest, getContestNameLabel } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/math_and_algorithm_provider.test.ts b/src/features/tasks/utils/contest-table/math_and_algorithm_provider.test.ts
index c972d89da..6b6235340 100644
--- a/src/features/tasks/utils/contest-table/math_and_algorithm_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/math_and_algorithm_provider.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { MathAndAlgorithmProvider } from './math_and_algorithm_provider';
 
diff --git a/src/features/tasks/utils/contest-table/math_and_algorithm_provider.ts b/src/features/tasks/utils/contest-table/math_and_algorithm_provider.ts
index 8ded8b1b8..959944d93 100644
--- a/src/features/tasks/utils/contest-table/math_and_algorithm_provider.ts
+++ b/src/features/tasks/utils/contest-table/math_and_algorithm_provider.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/tessoku_book_providers.test.ts b/src/features/tasks/utils/contest-table/tessoku_book_providers.test.ts
index 68241da1d..a649f2aa7 100644
--- a/src/features/tasks/utils/contest-table/tessoku_book_providers.test.ts
+++ b/src/features/tasks/utils/contest-table/tessoku_book_providers.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import {
   TessokuBookProvider,
diff --git a/src/features/tasks/utils/contest-table/tessoku_book_providers.ts b/src/features/tasks/utils/contest-table/tessoku_book_providers.ts
index 71e1af349..2f75eb3d7 100644
--- a/src/features/tasks/utils/contest-table/tessoku_book_providers.ts
+++ b/src/features/tasks/utils/contest-table/tessoku_book_providers.ts
@@ -3,10 +3,10 @@ import {
   type ContestTableDisplayConfig,
   TESSOKU_SECTIONS,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResult } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/tasks/utils/contest-table/typical90_provider.test.ts b/src/features/tasks/utils/contest-table/typical90_provider.test.ts
index a81473674..7c814bc5f 100644
--- a/src/features/tasks/utils/contest-table/typical90_provider.test.ts
+++ b/src/features/tasks/utils/contest-table/typical90_provider.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { TaskResults } from '#lib/types/task.js';
 
 import { Typical90Provider } from './typical90_provider';
 import { taskResultsForContestTableProvider } from '$features/tasks/fixtures/contest-table/contest_table_provider';
diff --git a/src/features/tasks/utils/contest-table/typical90_provider.ts b/src/features/tasks/utils/contest-table/typical90_provider.ts
index 8a2505ef2..08650fd3c 100644
--- a/src/features/tasks/utils/contest-table/typical90_provider.ts
+++ b/src/features/tasks/utils/contest-table/typical90_provider.ts
@@ -2,9 +2,9 @@ import {
   type ContestTableMetaData,
   type ContestTableDisplayConfig,
 } from '$features/tasks/types/contest-table/contest_table_provider';
-import type { TaskResult } from '$lib/types/task';
+import type { TaskResult } from '#lib/types/task.js';
 
-import { classifyContest } from '$lib/contests';
+import { classifyContest } from '#lib/contests/index.js';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 
diff --git a/src/features/votes/actions/vote_actions.ts b/src/features/votes/actions/vote_actions.ts
index e273b89c1..1698977c4 100644
--- a/src/features/votes/actions/vote_actions.ts
+++ b/src/features/votes/actions/vote_actions.ts
@@ -6,7 +6,7 @@ import {
   FORBIDDEN,
   INTERNAL_SERVER_ERROR,
   UNAUTHORIZED,
-} from '$lib/constants/http-response-status-codes';
+} from '#lib/constants/http-response-status-codes.js';
 
 import type { VoteAbsoluteGradeInput } from '$features/votes/zod/schema';
 
diff --git a/src/features/votes/components/RelativeEvaluationBadge.svelte b/src/features/votes/components/RelativeEvaluationBadge.svelte
index 04e5683b6..354def55d 100644
--- a/src/features/votes/components/RelativeEvaluationBadge.svelte
+++ b/src/features/votes/components/RelativeEvaluationBadge.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
   import { Tooltip } from 'flowbite-svelte';
 
-  import type { TaskGrade } from '$lib/types/task';
+  import type { TaskGrade } from '#lib/types/task.js';
   import {
     calcGradeDiff,
     getRelativeEvaluationLabel,
diff --git a/src/features/votes/components/VotableGrade.svelte b/src/features/votes/components/VotableGrade.svelte
index 578482d1a..d40cfe2ca 100644
--- a/src/features/votes/components/VotableGrade.svelte
+++ b/src/features/votes/components/VotableGrade.svelte
@@ -7,15 +7,15 @@
   import Check from '@lucide/svelte/icons/check';
   import FlaskConical from '@lucide/svelte/icons/flask-conical';
 
-  import { TaskGrade, getTaskGrade, type TaskResult } from '$lib/types/task';
-  import { errorMessageStore } from '$lib/stores/error_message';
+  import { TaskGrade, getTaskGrade, type TaskResult } from '#lib/types/task.js';
+  import { errorMessageStore } from '#lib/stores/error_message.js';
   import {
     fetchMyVote,
     submitVote,
     fetchMedianVote,
   } from '$features/votes/internal_clients/vote_grade';
 
-  import { getTaskGradeLabel } from '$lib/utils/task';
+  import { getTaskGradeLabel } from '#lib/utils/task.js';
   import { nonPendingGrades, resolveDisplayGrade } from '$features/votes/utils/grade_options';
   import { calcCenteredScrollTop } from '$features/votes/utils/grade_scroll_position';
   import {
@@ -24,10 +24,10 @@
     getRelativeEvaluationJapaneseLabel,
     getRelativeEvaluationColorClass,
   } from '$features/votes/utils/relative_evaluation';
-  import { SIGNUP_PAGE, LOGIN_PAGE, EDIT_PROFILE_PAGE } from '$lib/constants/navbar-links';
+  import { SIGNUP_PAGE, LOGIN_PAGE, EDIT_PROFILE_PAGE } from '#lib/constants/navbar-links.js';
 
-  import GradeLabel from '$lib/components/GradeLabel.svelte';
-  import InputFieldWrapper from '$lib/components/InputFieldWrapper.svelte';
+  import GradeLabel from '#lib/components/GradeLabel.svelte';
+  import InputFieldWrapper from '#lib/components/InputFieldWrapper.svelte';
   import RelativeEvaluationBadge from '$features/votes/components/RelativeEvaluationBadge.svelte';
 
   interface Props {
diff --git a/src/features/votes/components/VoteDonutChart.svelte b/src/features/votes/components/VoteDonutChart.svelte
index fdf8af91b..b44473904 100644
--- a/src/features/votes/components/VoteDonutChart.svelte
+++ b/src/features/votes/components/VoteDonutChart.svelte
@@ -1,9 +1,9 @@
 <script lang="ts">
   import type { VotedGradeCounter } from '@prisma/client';
-  import { TaskGrade } from '$lib/types/task';
+  import { TaskGrade } from '#lib/types/task.js';
   import type { DonutSegment } from '$features/votes/types/donut_graph';
 
-  import { getTaskGradeColor, getTaskGradeLabel } from '$lib/utils/task';
+  import { getTaskGradeColor, getTaskGradeLabel } from '#lib/utils/task.js';
   import { nonPendingGrades } from '$features/votes/utils/grade_options';
   import {
     buildDonutSegments,
diff --git a/src/features/votes/internal_clients/vote_grade.test.ts b/src/features/votes/internal_clients/vote_grade.test.ts
index af125b2e2..c09c2f1ff 100644
--- a/src/features/votes/internal_clients/vote_grade.test.ts
+++ b/src/features/votes/internal_clients/vote_grade.test.ts
@@ -1,11 +1,11 @@
 import { describe, test, expect, beforeEach, afterEach, vi } from 'vitest';
 import nock from 'nock';
 
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 
 import { fetchMyVote, submitVote, fetchMedianVote } from './vote_grade';
 
-import * as statusCodes from '$lib/constants/http-response-status-codes';
+import * as statusCodes from '#lib/constants/http-response-status-codes.js';
 
 const BASE_URL = 'http://localhost';
 const TASK_ID = 'abc_a';
diff --git a/src/features/votes/internal_clients/vote_grade.ts b/src/features/votes/internal_clients/vote_grade.ts
index 96fabbeb2..791fcb763 100644
--- a/src/features/votes/internal_clients/vote_grade.ts
+++ b/src/features/votes/internal_clients/vote_grade.ts
@@ -1,5 +1,5 @@
-import type { TaskGrade } from '$lib/types/task';
-import { isValidTaskGrade } from '$lib/utils/task_grade';
+import type { TaskGrade } from '#lib/types/task.js';
+import { isValidTaskGrade } from '#lib/utils/task_grade.js';
 
 /**
  * Fetches the current user's vote grade for a given task.
diff --git a/src/features/votes/server/cache.test.ts b/src/features/votes/server/cache.test.ts
index 7775076ca..7e8440e43 100644
--- a/src/features/votes/server/cache.test.ts
+++ b/src/features/votes/server/cache.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect, vi, beforeEach, afterEach, afterAll } from 'vitest';
 
 import type { VotedGradeStatistics } from '@prisma/client';
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import type { TaskWithVoteInfo } from '$features/votes/services/vote_statistics';
 import {
   getCachedVoteStats,
diff --git a/src/features/votes/server/cache.ts b/src/features/votes/server/cache.ts
index ebecf1030..c3b69f0b8 100644
--- a/src/features/votes/server/cache.ts
+++ b/src/features/votes/server/cache.ts
@@ -1,4 +1,4 @@
-import { Cache } from '$lib/clients/cache';
+import { Cache } from '#lib/clients/cache.js';
 
 import type { VotedGradeStatistics } from '@prisma/client';
 
diff --git a/src/features/votes/services/vote_grade.test.ts b/src/features/votes/services/vote_grade.test.ts
index 6734225bf..5aba00e6a 100644
--- a/src/features/votes/services/vote_grade.test.ts
+++ b/src/features/votes/services/vote_grade.test.ts
@@ -8,7 +8,7 @@ vi.mock('$features/votes/server/cache', () => ({
   invalidateVoteCaches: vi.fn(),
 }));
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     voteGrade: {
       findUnique: vi.fn(),
@@ -29,7 +29,7 @@ vi.mock('$lib/server/database', () => ({
   },
 }));
 
-import prisma from '$lib/server/database';
+import prisma from '#lib/server/database.js';
 import { invalidateVoteCaches } from '$features/votes/server/cache';
 
 // ---------------------------------------------------------------------------
diff --git a/src/features/votes/services/vote_grade.ts b/src/features/votes/services/vote_grade.ts
index dedea47e9..adec87c04 100644
--- a/src/features/votes/services/vote_grade.ts
+++ b/src/features/votes/services/vote_grade.ts
@@ -1,6 +1,6 @@
-import { default as prisma } from '$lib/server/database';
+import { default as prisma } from '#lib/server/database.js';
 import { TaskGrade } from '@prisma/client';
-import { sha256 } from '$lib/utils/hash';
+import { sha256 } from '#lib/utils/hash.js';
 import type { VoteGradeResult } from '$features/votes/types/vote_result';
 import { computeMedianGrade } from '$features/votes/utils/median';
 import {
diff --git a/src/features/votes/services/vote_statistics.test.ts b/src/features/votes/services/vote_statistics.test.ts
index 577994230..8f05c383c 100644
--- a/src/features/votes/services/vote_statistics.test.ts
+++ b/src/features/votes/services/vote_statistics.test.ts
@@ -12,7 +12,7 @@ import {
   getAllVoteCounters,
 } from './vote_statistics';
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     voteGrade: {
       findUnique: vi.fn(),
@@ -35,7 +35,7 @@ vi.mock('$features/votes/server/cache', () => ({
   getCachedAllTasksWithVoteInfo: (fetchFn: () => Promise<unknown>) => fetchFn(),
 }));
 
-import prisma from '$lib/server/database';
+import prisma from '#lib/server/database.js';
 
 // ---------------------------------------------------------------------------
 // Type aliases
diff --git a/src/features/votes/services/vote_statistics.ts b/src/features/votes/services/vote_statistics.ts
index 60db5299f..e12ce19dd 100644
--- a/src/features/votes/services/vote_statistics.ts
+++ b/src/features/votes/services/vote_statistics.ts
@@ -1,4 +1,4 @@
-import { default as prisma } from '$lib/server/database';
+import { default as prisma } from '#lib/server/database.js';
 import { getCachedVoteStats, getCachedAllTasksWithVoteInfo } from '$features/votes/server/cache';
 
 import type { VotedGradeStatistics, VotedGradeCounter, TaskGrade } from '@prisma/client';
diff --git a/src/features/votes/types/donut_graph.ts b/src/features/votes/types/donut_graph.ts
index b48de66af..f168f517e 100644
--- a/src/features/votes/types/donut_graph.ts
+++ b/src/features/votes/types/donut_graph.ts
@@ -1,4 +1,4 @@
-import type { TaskGrade } from '$lib/types/task';
+import type { TaskGrade } from '#lib/types/task.js';
 
 /** A single arc segment of the vote distribution donut chart. */
 export type DonutSegment = {
diff --git a/src/features/votes/types/vote_result.ts b/src/features/votes/types/vote_result.ts
index 696bd24c7..e4698aa43 100644
--- a/src/features/votes/types/vote_result.ts
+++ b/src/features/votes/types/vote_result.ts
@@ -1,4 +1,4 @@
-import type { TaskGrade } from '$lib/types/task';
+import type { TaskGrade } from '#lib/types/task.js';
 
 /** Result of fetching a single user's vote for a task. */
 export type VoteGradeResult = {
diff --git a/src/features/votes/utils/donut_chart.test.ts b/src/features/votes/utils/donut_chart.test.ts
index 11c74049a..6c6c2a1bc 100644
--- a/src/features/votes/utils/donut_chart.test.ts
+++ b/src/features/votes/utils/donut_chart.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import { buildDonutSegments, buildArcPath, calcPointOnCircle, MIN_LABEL_PCT } from './donut_chart';
 
 const GRADE_A = TaskGrade.Q1;
diff --git a/src/features/votes/utils/donut_chart.ts b/src/features/votes/utils/donut_chart.ts
index 66a54510f..e2765806d 100644
--- a/src/features/votes/utils/donut_chart.ts
+++ b/src/features/votes/utils/donut_chart.ts
@@ -1,4 +1,4 @@
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import type { DonutSegment, DonutSegments } from '$features/votes/types/donut_graph';
 
 export type { DonutSegment, DonutSegments };
diff --git a/src/features/votes/utils/grade_options.test.ts b/src/features/votes/utils/grade_options.test.ts
index e94792922..e2979a142 100644
--- a/src/features/votes/utils/grade_options.test.ts
+++ b/src/features/votes/utils/grade_options.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, it, test } from 'vitest';
 
-import { TaskGrade, taskGradeValues } from '$lib/types/task';
+import { TaskGrade, taskGradeValues } from '#lib/types/task.js';
 
 import { resolveDisplayGrade, nonPendingGrades, qGrades, dGrades } from './grade_options';
 
diff --git a/src/features/votes/utils/grade_options.ts b/src/features/votes/utils/grade_options.ts
index 1a34a8488..6b7c4510e 100644
--- a/src/features/votes/utils/grade_options.ts
+++ b/src/features/votes/utils/grade_options.ts
@@ -1,4 +1,4 @@
-import { taskGradeValues, TaskGrade } from '$lib/types/task';
+import { taskGradeValues, TaskGrade } from '#lib/types/task.js';
 
 /** All grade values except PENDING, used for vote buttons and distribution display. */
 /** All task grades excluding PENDING, in display order (Q11 → D6). */
diff --git a/src/features/votes/utils/median.ts b/src/features/votes/utils/median.ts
index ede766196..ef1e3d1b4 100644
--- a/src/features/votes/utils/median.ts
+++ b/src/features/votes/utils/median.ts
@@ -1,5 +1,5 @@
 import { TaskGrade } from '@prisma/client';
-import { getGradeOrder, taskGradeOrderInfinity } from '$lib/utils/task';
+import { getGradeOrder, taskGradeOrderInfinity } from '#lib/utils/task.js';
 import { MIN_VOTES_FOR_STATISTICS } from '$features/votes/constants/statistics';
 
 /** Maps grade order (1=Q11 … 17=D6) back to the corresponding TaskGrade enum value. */
diff --git a/src/features/votes/utils/relative_evaluation.test.ts b/src/features/votes/utils/relative_evaluation.test.ts
index c4c4b43d5..c405f8ab4 100644
--- a/src/features/votes/utils/relative_evaluation.test.ts
+++ b/src/features/votes/utils/relative_evaluation.test.ts
@@ -1,6 +1,6 @@
 import { describe, expect, test } from 'vitest';
 
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import {
   calcGradeDiff,
   getRelativeEvaluationLabel,
diff --git a/src/features/votes/utils/relative_evaluation.ts b/src/features/votes/utils/relative_evaluation.ts
index 99f12fa7d..f77549919 100644
--- a/src/features/votes/utils/relative_evaluation.ts
+++ b/src/features/votes/utils/relative_evaluation.ts
@@ -1,5 +1,5 @@
-import type { TaskGrade } from '$lib/types/task';
-import { getGradeOrder } from '$lib/utils/task';
+import type { TaskGrade } from '#lib/types/task.js';
+import { getGradeOrder } from '#lib/utils/task.js';
 
 /**
  * Computes the difference in grade order between the median vote and the official grade.
diff --git a/src/features/workbooks/components/detail/CommentAndHint.svelte b/src/features/workbooks/components/detail/CommentAndHint.svelte
index 169b75b00..be3ddc09b 100644
--- a/src/features/workbooks/components/detail/CommentAndHint.svelte
+++ b/src/features/workbooks/components/detail/CommentAndHint.svelte
@@ -2,7 +2,7 @@
   import { Tooltip } from 'flowbite-svelte';
   import Lightbulb from '@lucide/svelte/icons/lightbulb';
 
-  import { TOOLTIP_CLASS_BASE } from '$lib/constants/tailwind-helper';
+  import { TOOLTIP_CLASS_BASE } from '#lib/constants/tailwind-helper.js';
 
   interface Props {
     uniqueId: string;
diff --git a/src/features/workbooks/components/detail/WorkBookTasksTable.svelte b/src/features/workbooks/components/detail/WorkBookTasksTable.svelte
index cfbdcd86e..c8d4630c5 100644
--- a/src/features/workbooks/components/detail/WorkBookTasksTable.svelte
+++ b/src/features/workbooks/components/detail/WorkBookTasksTable.svelte
@@ -11,11 +11,11 @@
   } from 'flowbite-svelte';
   import Trash from '@lucide/svelte/icons/trash';
 
-  import GradeLabel from '$lib/components/GradeLabel.svelte';
-  import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
+  import GradeLabel from '#lib/components/GradeLabel.svelte';
+  import ExternalLinkWrapper from '#lib/components/ExternalLinkWrapper.svelte';
 
-  import { addContestNameToTaskIndex } from '$lib/contests';
-  import { getTaskUrl, removeTaskIndexFromTitle } from '$lib/utils/task';
+  import { addContestNameToTaskIndex } from '#lib/contests/index.js';
+  import { getTaskUrl, removeTaskIndexFromTitle } from '#lib/utils/task.js';
 
   import type {
     WorkBookTasksBase,
@@ -25,7 +25,7 @@
     WorkBookTasksEdit,
     WorkBookTaskEdit,
   } from '$features/workbooks/types/workbook';
-  import type { Task } from '$lib/types/task';
+  import type { Task } from '#lib/types/task.js';
 
   interface Props {
     tasksMapByIds: Map<string, Task>;
diff --git a/src/features/workbooks/components/list/AcceptedCounter.svelte b/src/features/workbooks/components/list/AcceptedCounter.svelte
index 53133f481..876750f5c 100644
--- a/src/features/workbooks/components/list/AcceptedCounter.svelte
+++ b/src/features/workbooks/components/list/AcceptedCounter.svelte
@@ -1,10 +1,10 @@
 <script lang="ts">
-  import type { TaskResults } from '$lib/types/task';
+  import type { TaskResults } from '#lib/types/task.js';
   import type { WorkBookTaskBase } from '$features/workbooks/types/workbook';
 
-  import AcceptedCounter from '$lib/components/SubmissionStatus/AcceptedCounter.svelte';
+  import AcceptedCounter from '#lib/components/SubmissionStatus/AcceptedCounter.svelte';
 
-  import { countAcceptedTasks, countAllTasks } from '$lib/utils/task';
+  import { countAcceptedTasks, countAllTasks } from '#lib/utils/task.js';
 
   interface Props {
     workBookTasks: WorkBookTaskBase[];
diff --git a/src/features/workbooks/components/list/CreatedByUserTable.svelte b/src/features/workbooks/components/list/CreatedByUserTable.svelte
index b2cee4554..3b5a170bf 100644
--- a/src/features/workbooks/components/list/CreatedByUserTable.svelte
+++ b/src/features/workbooks/components/list/CreatedByUserTable.svelte
@@ -17,7 +17,7 @@
   import WorkbookAuthorActionsCell from '$features/workbooks/components/list/WorkbookAuthorActionsCell.svelte';
   import EmptyWorkbookList from '$features/workbooks/components/list/EmptyWorkbookList.svelte';
 
-  import { canRead } from '$lib/utils/authorship';
+  import { canRead } from '#lib/utils/authorship.js';
   import { getTaskResult } from '$features/workbooks/utils/workbooks';
 
   let { workbooks, userId, role, taskResults }: SolutionTableProps = $props();
diff --git a/src/features/workbooks/components/list/CurriculumTable.svelte b/src/features/workbooks/components/list/CurriculumTable.svelte
index ea0a4df0c..33c70bda0 100644
--- a/src/features/workbooks/components/list/CurriculumTable.svelte
+++ b/src/features/workbooks/components/list/CurriculumTable.svelte
@@ -10,7 +10,7 @@
   import WorkbookCompletionCell from '$features/workbooks/components/list/WorkbookCompletionCell.svelte';
   import WorkbookAuthorActionsCell from '$features/workbooks/components/list/WorkbookAuthorActionsCell.svelte';
 
-  import { canRead } from '$lib/utils/authorship';
+  import { canRead } from '#lib/utils/authorship.js';
   import { getGradeMode, getTaskResult } from '$features/workbooks/utils/workbooks';
 
   let { workbooks, gradeModesEachWorkbook, userId, role, taskResults }: WorkbookTableProps =
diff --git a/src/features/workbooks/components/list/CurriculumWorkBookList.svelte b/src/features/workbooks/components/list/CurriculumWorkBookList.svelte
index 034998bdb..14865ee2f 100644
--- a/src/features/workbooks/components/list/CurriculumWorkBookList.svelte
+++ b/src/features/workbooks/components/list/CurriculumWorkBookList.svelte
@@ -1,20 +1,20 @@
 <script lang="ts">
   import { Button, Toggle } from 'flowbite-svelte';
 
-  import type { Roles } from '$lib/types/user';
-  import { TaskGrade, type TaskResults } from '$lib/types/task';
+  import type { Roles } from '#lib/types/user.js';
+  import { TaskGrade, type TaskResults } from '#lib/types/task.js';
   import { type WorkbooksList } from '$features/workbooks/types/workbook';
 
   import { replenishmentWorkBooksStore } from '$features/workbooks/stores/replenishment_workbook.svelte';
 
-  import { getTaskGradeLabel } from '$lib/utils/task';
+  import { getTaskGradeLabel } from '#lib/utils/task.js';
   import {
     countReadableWorkbooks,
     partitionWorkbooksAsMainAndReplenished,
   } from '$features/workbooks/utils/workbooks';
 
-  import TooltipWrapper from '$lib/components/TooltipWrapper.svelte';
-  import LabelWithTooltips from '$lib/components/LabelWithTooltips.svelte';
+  import TooltipWrapper from '#lib/components/TooltipWrapper.svelte';
+  import LabelWithTooltips from '#lib/components/LabelWithTooltips.svelte';
   import CurriculumTable from '$features/workbooks/components/list/CurriculumTable.svelte';
   import EmptyWorkbookList from '$features/workbooks/components/list/EmptyWorkbookList.svelte';
 
diff --git a/src/features/workbooks/components/list/GradeTableBodyCell.svelte b/src/features/workbooks/components/list/GradeTableBodyCell.svelte
index 2701ee6d8..54ead48ba 100644
--- a/src/features/workbooks/components/list/GradeTableBodyCell.svelte
+++ b/src/features/workbooks/components/list/GradeTableBodyCell.svelte
@@ -1,9 +1,9 @@
 <script lang="ts">
   import { TableBodyCell } from 'flowbite-svelte';
 
-  import type { TaskGrade } from '$lib/types/task';
+  import type { TaskGrade } from '#lib/types/task.js';
 
-  import GradeLabel from '$lib/components/GradeLabel.svelte';
+  import GradeLabel from '#lib/components/GradeLabel.svelte';
 
   interface Props {
     taskGrade: TaskGrade;
diff --git a/src/features/workbooks/components/list/SolutionTable.svelte b/src/features/workbooks/components/list/SolutionTable.svelte
index 50bce8087..7bac24138 100644
--- a/src/features/workbooks/components/list/SolutionTable.svelte
+++ b/src/features/workbooks/components/list/SolutionTable.svelte
@@ -9,7 +9,7 @@
   import WorkbookCompletionCell from '$features/workbooks/components/list/WorkbookCompletionCell.svelte';
   import WorkbookAuthorActionsCell from '$features/workbooks/components/list/WorkbookAuthorActionsCell.svelte';
 
-  import { canRead } from '$lib/utils/authorship';
+  import { canRead } from '#lib/utils/authorship.js';
   import { getTaskResult } from '$features/workbooks/utils/workbooks';
 
   let { workbooks, userId, role, taskResults }: SolutionTableProps = $props();
diff --git a/src/features/workbooks/components/list/SolutionWorkBookList.svelte b/src/features/workbooks/components/list/SolutionWorkBookList.svelte
index 4eb4b384a..d82d1a21f 100644
--- a/src/features/workbooks/components/list/SolutionWorkBookList.svelte
+++ b/src/features/workbooks/components/list/SolutionWorkBookList.svelte
@@ -1,8 +1,8 @@
 <script lang="ts">
   import { Button } from 'flowbite-svelte';
 
-  import type { Roles } from '$lib/types/user';
-  import type { TaskResults } from '$lib/types/task';
+  import type { Roles } from '#lib/types/user.js';
+  import type { TaskResults } from '#lib/types/task.js';
   import type { WorkbooksList } from '$features/workbooks/types/workbook';
   import {
     SolutionCategory,
diff --git a/src/features/workbooks/components/list/WorkBookList.svelte b/src/features/workbooks/components/list/WorkBookList.svelte
index 4a2410756..6012ed0a5 100644
--- a/src/features/workbooks/components/list/WorkBookList.svelte
+++ b/src/features/workbooks/components/list/WorkBookList.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
-  import { Roles } from '$lib/types/user';
-  import { TaskGrade, type TaskResults } from '$lib/types/task';
+  import { Roles } from '#lib/types/user.js';
+  import { TaskGrade, type TaskResults } from '#lib/types/task.js';
   import { WorkBookType, type WorkbooksList } from '$features/workbooks/types/workbook';
   import {
     type SolutionCategory,
diff --git a/src/features/workbooks/components/list/WorkbookAuthorActionsCell.svelte b/src/features/workbooks/components/list/WorkbookAuthorActionsCell.svelte
index 1d336bd1a..d1d874a9d 100644
--- a/src/features/workbooks/components/list/WorkbookAuthorActionsCell.svelte
+++ b/src/features/workbooks/components/list/WorkbookAuthorActionsCell.svelte
@@ -4,10 +4,10 @@
 
   import { TableBodyCell } from 'flowbite-svelte';
 
-  import type { Roles } from '$lib/types/user';
+  import type { Roles } from '#lib/types/user.js';
   import type { WorkbookList } from '$features/workbooks/types/workbook';
 
-  import { canEdit, canDelete } from '$lib/utils/authorship';
+  import { canEdit, canDelete } from '#lib/utils/authorship.js';
   import { getUrlSlugFrom } from '$features/workbooks/utils/workbooks';
 
   interface Props {
diff --git a/src/features/workbooks/components/list/WorkbookCompletionCell.svelte b/src/features/workbooks/components/list/WorkbookCompletionCell.svelte
index 9fa1aee1b..61f053436 100644
--- a/src/features/workbooks/components/list/WorkbookCompletionCell.svelte
+++ b/src/features/workbooks/components/list/WorkbookCompletionCell.svelte
@@ -1,10 +1,10 @@
 <script lang="ts">
   import { TableBodyCell } from 'flowbite-svelte';
 
-  import type { TaskResults } from '$lib/types/task';
+  import type { TaskResults } from '#lib/types/task.js';
   import type { WorkBookTaskBase } from '$features/workbooks/types/workbook';
 
-  import CompletedTasks from '$lib/components/Trophies/CompletedTasks.svelte';
+  import CompletedTasks from '#lib/components/Trophies/CompletedTasks.svelte';
 
   interface Props {
     workBookTasks: WorkBookTaskBase[];
diff --git a/src/features/workbooks/components/list/WorkbookProgressCell.svelte b/src/features/workbooks/components/list/WorkbookProgressCell.svelte
index d682baf85..15a46718b 100644
--- a/src/features/workbooks/components/list/WorkbookProgressCell.svelte
+++ b/src/features/workbooks/components/list/WorkbookProgressCell.svelte
@@ -1,10 +1,10 @@
 <script lang="ts">
   import { TableBodyCell } from 'flowbite-svelte';
 
-  import type { TaskResults } from '$lib/types/task';
+  import type { TaskResults } from '#lib/types/task.js';
   import type { WorkBookTasksBase } from '$features/workbooks/types/workbook';
 
-  import ThermometerProgressBar from '$lib/components/ThermometerProgressBar.svelte';
+  import ThermometerProgressBar from '#lib/components/ThermometerProgressBar.svelte';
   import AcceptedCounter from '$features/workbooks/components/list/AcceptedCounter.svelte';
 
   interface Props {
diff --git a/src/features/workbooks/components/list/WorkbookTabItem.svelte b/src/features/workbooks/components/list/WorkbookTabItem.svelte
index 55d5e7d5b..aa611d82f 100644
--- a/src/features/workbooks/components/list/WorkbookTabItem.svelte
+++ b/src/features/workbooks/components/list/WorkbookTabItem.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
   import type { Snippet } from 'svelte';
-  import TabItemWrapper from '$lib/components/Tabs/TabItemWrapper.svelte';
+  import TabItemWrapper from '#lib/components/Tabs/TabItemWrapper.svelte';
 
   interface Props {
     isOpen?: boolean;
diff --git a/src/features/workbooks/components/shared/WorkBookForm.svelte b/src/features/workbooks/components/shared/WorkBookForm.svelte
index b287f14e3..058ccc906 100644
--- a/src/features/workbooks/components/shared/WorkBookForm.svelte
+++ b/src/features/workbooks/components/shared/WorkBookForm.svelte
@@ -1,16 +1,16 @@
 <script lang="ts">
   import { Breadcrumb, BreadcrumbItem } from 'flowbite-svelte';
 
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
   import WorkBookInputFields from '$features/workbooks/components/shared/WorkBookInputFields.svelte';
   import WorkBookTasksTable from '$features/workbooks/components/detail/WorkBookTasksTable.svelte';
-  import TaskSearchBox from '$lib/components/TaskSearchBox.svelte';
-  import InputFieldWrapper from '$lib/components/InputFieldWrapper.svelte';
-  import SubmissionButton from '$lib/components/SubmissionButton.svelte';
+  import TaskSearchBox from '#lib/components/TaskSearchBox.svelte';
+  import InputFieldWrapper from '#lib/components/InputFieldWrapper.svelte';
+  import SubmissionButton from '#lib/components/SubmissionButton.svelte';
 
-  import { preventEnterKey } from '$lib/actions/prevent_enter_key';
+  import { preventEnterKey } from '#lib/actions/prevent_enter_key.js';
 
-  import type { Task, Tasks } from '$lib/types/task';
+  import type { Task, Tasks } from '#lib/types/task.js';
   import type {
     WorkBookTaskCreate,
     WorkBookTasksCreate,
diff --git a/src/features/workbooks/components/shared/WorkBookInputFields.svelte b/src/features/workbooks/components/shared/WorkBookInputFields.svelte
index ea50a2150..416a4dd89 100644
--- a/src/features/workbooks/components/shared/WorkBookInputFields.svelte
+++ b/src/features/workbooks/components/shared/WorkBookInputFields.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
-  import MessageHelperWrapper from '$lib/components/MessageHelperWrapper.svelte';
-  import InputFieldWrapper from '$lib/components/InputFieldWrapper.svelte';
-  import SelectWrapper from '$lib/components/SelectWrapper.svelte';
+  import MessageHelperWrapper from '#lib/components/MessageHelperWrapper.svelte';
+  import InputFieldWrapper from '#lib/components/InputFieldWrapper.svelte';
+  import SelectWrapper from '#lib/components/SelectWrapper.svelte';
   import { WorkBookType } from '$features/workbooks/types/workbook';
 
   interface Props {
diff --git a/src/features/workbooks/fixtures/workbook_placements.ts b/src/features/workbooks/fixtures/workbook_placements.ts
index 5476166a7..0079c218d 100644
--- a/src/features/workbooks/fixtures/workbook_placements.ts
+++ b/src/features/workbooks/fixtures/workbook_placements.ts
@@ -1,4 +1,4 @@
-import { TaskGrade, type Task } from '$lib/types/task';
+import { TaskGrade, type Task } from '#lib/types/task.js';
 import { WorkBookType } from '$features/workbooks/types/workbook';
 import {
   SolutionCategory,
diff --git a/src/features/workbooks/server/cache.ts b/src/features/workbooks/server/cache.ts
index 50bf5d546..042b9ca60 100644
--- a/src/features/workbooks/server/cache.ts
+++ b/src/features/workbooks/server/cache.ts
@@ -1,4 +1,4 @@
-import { Cache, DEFAULT_CACHE_TTL } from '$lib/clients/cache';
+import { Cache, DEFAULT_CACHE_TTL } from '#lib/clients/cache.js';
 import type { WorkbooksWithAuthors } from '$features/workbooks/types/workbook';
 
 const BY_USER_KEY = 'workbooks_by_user';
diff --git a/src/features/workbooks/services/workbook_placements/crud.test.ts b/src/features/workbooks/services/workbook_placements/crud.test.ts
index 6d69008cc..bfe252253 100644
--- a/src/features/workbooks/services/workbook_placements/crud.test.ts
+++ b/src/features/workbooks/services/workbook_placements/crud.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect, vi } from 'vitest';
 
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import { WorkBookType } from '$features/workbooks/types/workbook';
 import {
   SolutionCategory,
@@ -26,7 +26,7 @@ import {
   unplacedSolutionWorkbooks,
 } from '$features/workbooks/fixtures/workbook_placements';
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     workBook: {
       findMany: vi.fn(),
@@ -40,7 +40,7 @@ vi.mock('$lib/server/database', () => ({
   },
 }));
 
-import prisma from '$lib/server/database';
+import prisma from '#lib/server/database.js';
 
 function mockFindMany(placements: WorkBookPlacements) {
   vi.mocked(prisma.workBookPlacement.findMany).mockResolvedValue(
diff --git a/src/features/workbooks/services/workbook_placements/crud.ts b/src/features/workbooks/services/workbook_placements/crud.ts
index 3391deff2..48b8a3331 100644
--- a/src/features/workbooks/services/workbook_placements/crud.ts
+++ b/src/features/workbooks/services/workbook_placements/crud.ts
@@ -1,4 +1,4 @@
-import prisma from '$lib/server/database';
+import prisma from '#lib/server/database.js';
 
 import {
   type WorkBookPlacement,
diff --git a/src/features/workbooks/services/workbook_placements/initializers.test.ts b/src/features/workbooks/services/workbook_placements/initializers.test.ts
index 6e9bf607a..6a78a2656 100644
--- a/src/features/workbooks/services/workbook_placements/initializers.test.ts
+++ b/src/features/workbooks/services/workbook_placements/initializers.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import {
   SolutionCategory,
   type UnplacedCurriculumRows,
diff --git a/src/features/workbooks/services/workbook_placements/initializers.ts b/src/features/workbooks/services/workbook_placements/initializers.ts
index f296522c4..1167287a8 100644
--- a/src/features/workbooks/services/workbook_placements/initializers.ts
+++ b/src/features/workbooks/services/workbook_placements/initializers.ts
@@ -1,4 +1,4 @@
-import { type Task, type TaskGrade } from '$lib/types/task';
+import { type Task, type TaskGrade } from '#lib/types/task.js';
 import {
   SolutionCategory,
   type WorkBooksWithTasks,
diff --git a/src/features/workbooks/services/workbooks.test.ts b/src/features/workbooks/services/workbooks.test.ts
index 0f1a7bede..e545b4a13 100644
--- a/src/features/workbooks/services/workbooks.test.ts
+++ b/src/features/workbooks/services/workbooks.test.ts
@@ -12,11 +12,11 @@ import {
   getAvailableSolutionCategories,
   getSolutionCategoryMapByWorkbookId,
 } from './workbooks';
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import { WorkBookType, type WorkBook } from '$features/workbooks/types/workbook';
 import { SolutionCategory } from '$features/workbooks/types/workbook_placement';
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     workBook: {
       findMany: vi.fn(),
@@ -36,7 +36,7 @@ vi.mock('$lib/server/database', () => ({
   },
 }));
 
-vi.mock('$lib/services/users', () => ({
+vi.mock('#lib/services/users.js', () => ({
   getUserById: vi.fn(),
 }));
 
@@ -46,8 +46,8 @@ vi.mock('$features/workbooks/server/cache', () => ({
   invalidateWorkbookCaches: vi.fn(),
 }));
 
-import prisma from '$lib/server/database';
-import * as usersCrud from '$lib/services/users';
+import prisma from '#lib/server/database.js';
+import * as usersCrud from '#lib/services/users.js';
 
 function prepareWorkBook(overrides: Partial<WorkBook> = {}): WorkBook {
   return {
diff --git a/src/features/workbooks/services/workbooks.ts b/src/features/workbooks/services/workbooks.ts
index 801f5085d..8e6841ab5 100644
--- a/src/features/workbooks/services/workbooks.ts
+++ b/src/features/workbooks/services/workbooks.ts
@@ -1,4 +1,4 @@
-import { default as db } from '$lib/server/database';
+import { default as db } from '#lib/server/database.js';
 
 import type {
   WorkBook,
@@ -19,7 +19,7 @@ import {
   getWorkBookTasks,
   validateRequiredFields,
 } from '$features/workbooks/services/workbook_tasks';
-import * as userCrud from '$lib/services/users';
+import * as userCrud from '#lib/services/users.js';
 
 import {
   getCachedWorkbooksByPlacement,
@@ -27,7 +27,7 @@ import {
   invalidateWorkbookCaches,
 } from '$features/workbooks/server/cache';
 
-import { sanitizeUrl } from '$lib/utils/url';
+import { sanitizeUrl } from '#lib/utils/url.js';
 import { parseWorkBookId, parseWorkBookUrlSlug } from '$features/workbooks/utils/workbook';
 import { buildPlacementKey } from '$features/workbooks/utils/workbooks';
 
diff --git a/src/features/workbooks/types/workbook.ts b/src/features/workbooks/types/workbook.ts
index 08631ada1..4177f4fa1 100644
--- a/src/features/workbooks/types/workbook.ts
+++ b/src/features/workbooks/types/workbook.ts
@@ -1,6 +1,6 @@
 import type { WorkBookType as WorkBookTypeOrigin } from '@prisma/client';
-import type { Roles } from '$lib/types/user';
-import type { TaskGrade, TaskResults } from '$lib/types/task';
+import type { Roles } from '#lib/types/user.js';
+import type { TaskGrade, TaskResults } from '#lib/types/task.js';
 
 export type WorkBookBase = {
   title: string;
diff --git a/src/features/workbooks/types/workbook_placement.ts b/src/features/workbooks/types/workbook_placement.ts
index 942fb2a08..45e8cf7a5 100644
--- a/src/features/workbooks/types/workbook_placement.ts
+++ b/src/features/workbooks/types/workbook_placement.ts
@@ -1,5 +1,5 @@
 import type { SolutionCategory as SolutionCategoryOrigin } from '@prisma/client';
-import type { TaskGrade } from '$lib/types/task';
+import type { TaskGrade } from '#lib/types/task.js';
 import type { WorkBookTaskBase } from '$features/workbooks/types/workbook';
 import { WorkBookType as WorkBookTypeConst } from '$features/workbooks/types/workbook';
 
diff --git a/src/features/workbooks/utils/solution_category_group.test.ts b/src/features/workbooks/utils/solution_category_group.test.ts
index 93a0d5c0c..4b4e66655 100644
--- a/src/features/workbooks/utils/solution_category_group.test.ts
+++ b/src/features/workbooks/utils/solution_category_group.test.ts
@@ -1,5 +1,5 @@
 import { describe, test, expect } from 'vitest';
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 import { SolutionCategory } from '$features/workbooks/types/workbook_placement';
 import type { WorkbooksList } from '$features/workbooks/types/workbook';
 import { groupBySolutionCategory, filterGroupsByRole } from './solution_category_group';
diff --git a/src/features/workbooks/utils/solution_category_group.ts b/src/features/workbooks/utils/solution_category_group.ts
index 55da2f95f..bb7c27082 100644
--- a/src/features/workbooks/utils/solution_category_group.ts
+++ b/src/features/workbooks/utils/solution_category_group.ts
@@ -1,4 +1,4 @@
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 import type { WorkbooksList } from '$features/workbooks/types/workbook';
 import { SolutionCategory } from '$features/workbooks/types/workbook_placement';
 
diff --git a/src/features/workbooks/utils/workbook.ts b/src/features/workbooks/utils/workbook.ts
index 9ec43230d..84cc2b5b6 100644
--- a/src/features/workbooks/utils/workbook.ts
+++ b/src/features/workbooks/utils/workbook.ts
@@ -1,4 +1,4 @@
-import { isValidUrlSlug } from '$lib/utils/url';
+import { isValidUrlSlug } from '#lib/utils/url.js';
 
 // See:
 // https://developer.mozilla.org/ja/docs/Web/JavaScript/Reference/Global_Objects/parseInt
diff --git a/src/features/workbooks/utils/workbook_tasks.test.ts b/src/features/workbooks/utils/workbook_tasks.test.ts
index 4a69e9a67..c5f5b85dd 100644
--- a/src/features/workbooks/utils/workbook_tasks.test.ts
+++ b/src/features/workbooks/utils/workbook_tasks.test.ts
@@ -1,7 +1,7 @@
 import { expect, test } from 'vitest';
 
-import type { Task, Tasks } from '$lib/types/task';
-import { TaskGrade } from '$lib/types/task';
+import type { Task, Tasks } from '#lib/types/task.js';
+import { TaskGrade } from '#lib/types/task.js';
 import type {
   WorkBookTasksBase,
   WorkBookTasksCreate,
diff --git a/src/features/workbooks/utils/workbook_tasks.ts b/src/features/workbooks/utils/workbook_tasks.ts
index a40f731aa..f11aa2425 100644
--- a/src/features/workbooks/utils/workbook_tasks.ts
+++ b/src/features/workbooks/utils/workbook_tasks.ts
@@ -1,4 +1,4 @@
-import type { Task } from '$lib/types/task';
+import type { Task } from '#lib/types/task.js';
 import type {
   WorkBookTaskBase,
   WorkBookTasksBase,
diff --git a/src/features/workbooks/utils/workbook_url_params.test.ts b/src/features/workbooks/utils/workbook_url_params.test.ts
index 69c2845fd..a001d8e43 100644
--- a/src/features/workbooks/utils/workbook_url_params.test.ts
+++ b/src/features/workbooks/utils/workbook_url_params.test.ts
@@ -1,5 +1,5 @@
 import { describe, test, expect } from 'vitest';
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import { SolutionCategory } from '$features/workbooks/types/workbook_placement';
 import { WorkBookTab } from '$features/workbooks/types/workbook';
 import {
diff --git a/src/features/workbooks/utils/workbook_url_params.ts b/src/features/workbooks/utils/workbook_url_params.ts
index a427aecb4..b33c20f33 100644
--- a/src/features/workbooks/utils/workbook_url_params.ts
+++ b/src/features/workbooks/utils/workbook_url_params.ts
@@ -1,4 +1,4 @@
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import { WorkBookTab, DEFAULT_WORKBOOK_TAB } from '$features/workbooks/types/workbook';
 import {
   SolutionCategory,
diff --git a/src/features/workbooks/utils/workbooks.test.ts b/src/features/workbooks/utils/workbooks.test.ts
index 24e8fff41..40b5d3e75 100644
--- a/src/features/workbooks/utils/workbooks.test.ts
+++ b/src/features/workbooks/utils/workbooks.test.ts
@@ -1,7 +1,7 @@
 import { describe, expect, test } from 'vitest';
 
-import { Roles } from '$lib/types/user';
-import { TaskGrade, type Task, type TaskResult } from '$lib/types/task';
+import { Roles } from '#lib/types/user.js';
+import { TaskGrade, type Task, type TaskResult } from '#lib/types/task.js';
 import { type WorkbookList, WorkBookType } from '$features/workbooks/types/workbook';
 import { SolutionCategory } from '$features/workbooks/types/workbook_placement';
 import type { PlacementQuery } from '$features/workbooks/types/workbook_placement';
diff --git a/src/features/workbooks/utils/workbooks.ts b/src/features/workbooks/utils/workbooks.ts
index a813a5e4c..97b017098 100644
--- a/src/features/workbooks/utils/workbooks.ts
+++ b/src/features/workbooks/utils/workbooks.ts
@@ -1,11 +1,11 @@
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 import {
   TaskGrade,
   type Task,
   type TaskGrades,
   type TaskResult,
   type TaskResults,
-} from '$lib/types/task';
+} from '#lib/types/task.js';
 import type {
   WorkBook,
   WorkbookList,
@@ -16,8 +16,8 @@ import type {
 import { WorkBookType as WorkBookTypeConst } from '$features/workbooks/types/workbook';
 import type { PlacementQuery } from '$features/workbooks/types/workbook_placement';
 
-import { isAdmin, canRead } from '$lib/utils/authorship';
-import { calcGradeMode } from '$lib/utils/task';
+import { isAdmin, canRead } from '#lib/utils/authorship.js';
+import { calcGradeMode } from '#lib/utils/task.js';
 
 export function buildPlacementKey(query: PlacementQuery, includeUnpublished: boolean): string {
   if (query.workBookType === WorkBookTypeConst.CURRICULUM) {
diff --git a/src/features/workbooks/zod/schema.test.ts b/src/features/workbooks/zod/schema.test.ts
index d8f1a8d65..c4bc84204 100644
--- a/src/features/workbooks/zod/schema.test.ts
+++ b/src/features/workbooks/zod/schema.test.ts
@@ -3,7 +3,7 @@ import { type ZodSchema } from 'zod';
 import { superValidate } from 'sveltekit-superforms/server';
 import { zod4 } from 'sveltekit-superforms/adapters';
 
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import { WorkBookType, type WorkBookTasks } from '$features/workbooks/types/workbook';
 import { SolutionCategory } from '$features/workbooks/types/workbook_placement';
 
diff --git a/src/features/workbooks/zod/schema.ts b/src/features/workbooks/zod/schema.ts
index 12496d35a..021c41af3 100644
--- a/src/features/workbooks/zod/schema.ts
+++ b/src/features/workbooks/zod/schema.ts
@@ -4,11 +4,11 @@
 // https://qiita.com/mpyw/items/886218e7b418dfed254b
 import { z } from 'zod';
 
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import { WorkBookType } from '$features/workbooks/types/workbook';
 import { SolutionCategory } from '$features/workbooks/types/workbook_placement';
 
-import { isValidUrl, isValidUrlSlug } from '$lib/utils/url';
+import { isValidUrl, isValidUrlSlug } from '#lib/utils/url.js';
 
 const workBookTaskSchema = z.object({
   workBookId: z.number().positive().optional(),
diff --git a/src/hooks.server.ts b/src/hooks.server.ts
index 53f489df7..361b4acbf 100644
--- a/src/hooks.server.ts
+++ b/src/hooks.server.ts
@@ -5,7 +5,7 @@ import type { Handle } from '@sveltejs/kit';
 
 import { createAuthRequest } from '$features/auth/server/auth';
 
-import * as userService from '$lib/services/users';
+import * as userService from '#lib/services/users.js';
 
 export const handle: Handle = async ({ event, resolve }) => {
   event.locals.auth = createAuthRequest(event);
diff --git a/src/lib/actions/prevent_enter_key.ts b/src/lib/actions/prevent_enter_key.ts
index 6d85dc4df..986b5f5fa 100644
--- a/src/lib/actions/prevent_enter_key.ts
+++ b/src/lib/actions/prevent_enter_key.ts
@@ -2,7 +2,7 @@
 //
 // 1. 任意のSvelteコンポーネントにインポート
 // <script>
-//   import { preventEnterKey } from '$lib/actions/prevent_enter_key';
+//   import { preventEnterKey } from '#lib/actions/prevent_enter_key.js';
 // </script>
 
 // 2. formに use:preventEnterKey を追加
diff --git a/src/lib/actions/update_task_result.ts b/src/lib/actions/update_task_result.ts
index 26a7a8d2e..a9838801f 100644
--- a/src/lib/actions/update_task_result.ts
+++ b/src/lib/actions/update_task_result.ts
@@ -1,7 +1,7 @@
 import { fail } from '@sveltejs/kit';
 
-import * as crud from '$lib/services/task_results';
-import { BAD_REQUEST, UNAUTHORIZED } from '$lib/constants/http-response-status-codes';
+import * as crud from '#lib/services/task_results.js';
+import { BAD_REQUEST, UNAUTHORIZED } from '#lib/constants/http-response-status-codes.js';
 
 // HACK: clickを1回実行するとactionsが2回実行されてしまう。原因と修正方法が分かっていない状態。
 export const updateTaskResult = async (
diff --git a/src/lib/clients/aizu_online_judge/clients.test.ts b/src/lib/clients/aizu_online_judge/clients.test.ts
index 0c1039688..201522c5d 100644
--- a/src/lib/clients/aizu_online_judge/clients.test.ts
+++ b/src/lib/clients/aizu_online_judge/clients.test.ts
@@ -1,18 +1,18 @@
 import { describe, test, expect, beforeEach, afterEach, vi } from 'vitest';
 import nock from 'nock';
 
-vi.mock('$lib/utils/time', () => ({
+vi.mock('#lib/utils/time.js', () => ({
   delay: vi.fn().mockResolvedValue(undefined),
 }));
 
-import { HttpRequestClient } from '$lib/clients/http_client';
-import { ContestTaskCache } from '$lib/clients/cache_strategy';
-import { Cache } from '$lib/clients/cache';
+import { HttpRequestClient } from '#lib/clients/http_client.js';
+import { ContestTaskCache } from '#lib/clients/cache_strategy.js';
+import { Cache } from '#lib/clients/cache.js';
 
 import { AojCoursesApiClient, AojChallengesApiClient } from './clients';
 
-import type { ContestsForImport } from '$lib/contests/types/contest';
-import type { TasksForImport } from '$lib/types/task';
+import type { ContestsForImport } from '#lib/contests/types/contest.js';
+import type { TasksForImport } from '#lib/types/task.js';
 import type { AOJCourseAPI, AOJChallengeContestAPI, AOJTaskAPIs } from './types';
 
 import { loadMockData } from '../fixtures/helpers';
diff --git a/src/lib/clients/aizu_online_judge/clients.ts b/src/lib/clients/aizu_online_judge/clients.ts
index 9af340fdd..0dacee80f 100644
--- a/src/lib/clients/aizu_online_judge/clients.ts
+++ b/src/lib/clients/aizu_online_judge/clients.ts
@@ -1,9 +1,12 @@
-import { HttpRequestClient } from '$lib/clients/http_client';
-import { ContestTaskCache } from '$lib/clients/cache_strategy';
-import { getCachedOrFetchContests, getCachedOrFetchTasks } from '$lib/clients/contest_task_fetcher';
+import { HttpRequestClient } from '#lib/clients/http_client.js';
+import { ContestTaskCache } from '#lib/clients/cache_strategy.js';
+import {
+  getCachedOrFetchContests,
+  getCachedOrFetchTasks,
+} from '#lib/clients/contest_task_fetcher.js';
 
-import type { ContestsForImport } from '$lib/contests/types/contest';
-import type { TasksForImport } from '$lib/types/task';
+import type { ContestsForImport } from '#lib/contests/types/contest.js';
+import type { TasksForImport } from '#lib/types/task.js';
 
 import type {
   AOJCourseAPI,
diff --git a/src/lib/clients/aizu_online_judge/utils.ts b/src/lib/clients/aizu_online_judge/utils.ts
index cb22863f7..5406393d9 100644
--- a/src/lib/clients/aizu_online_judge/utils.ts
+++ b/src/lib/clients/aizu_online_judge/utils.ts
@@ -1,4 +1,4 @@
-import type { ContestForImport } from '$lib/contests/types/contest';
+import type { ContestForImport } from '#lib/contests/types/contest.js';
 
 import { PENDING } from './types';
 import type { AOJTaskAPI } from './types';
diff --git a/src/lib/clients/atcoder/atcoder_problems.test.ts b/src/lib/clients/atcoder/atcoder_problems.test.ts
index 9b78df8be..f33079ef6 100644
--- a/src/lib/clients/atcoder/atcoder_problems.test.ts
+++ b/src/lib/clients/atcoder/atcoder_problems.test.ts
@@ -1,14 +1,14 @@
 import { describe, test, expect, beforeAll, beforeEach, afterEach, vi } from 'vitest';
 import nock from 'nock';
 
-vi.mock('$lib/utils/time', () => ({
+vi.mock('#lib/utils/time.js', () => ({
   delay: vi.fn().mockResolvedValue(undefined),
 }));
 
-import type { ContestsForImport } from '$lib/contests/types/contest';
-import type { TasksForImport } from '$lib/types/task';
+import type { ContestsForImport } from '#lib/contests/types/contest.js';
+import type { TasksForImport } from '#lib/types/task.js';
 
-import { AtCoderProblemsApiClient } from '$lib/clients/atcoder/atcoder_problems';
+import { AtCoderProblemsApiClient } from '#lib/clients/atcoder/atcoder_problems.js';
 
 import { loadMockData } from '../fixtures/helpers';
 
diff --git a/src/lib/clients/atcoder/atcoder_problems.ts b/src/lib/clients/atcoder/atcoder_problems.ts
index 653509a57..2b0211093 100644
--- a/src/lib/clients/atcoder/atcoder_problems.ts
+++ b/src/lib/clients/atcoder/atcoder_problems.ts
@@ -1,9 +1,9 @@
-import { HttpRequestClient } from '$lib/clients/http_client';
+import { HttpRequestClient } from '#lib/clients/http_client.js';
 
-import type { ContestsForImport } from '$lib/contests/types/contest';
-import type { TasksForImport } from '$lib/types/task';
+import type { ContestsForImport } from '#lib/contests/types/contest.js';
+import type { TasksForImport } from '#lib/types/task.js';
 
-import { ATCODER_PROBLEMS_API_BASE_URL } from '$lib/constants/urls';
+import { ATCODER_PROBLEMS_API_BASE_URL } from '#lib/constants/urls.js';
 
 /**
  * The `AtCoderProblemsApiClient` class provides methods to interact with the AtCoder Problems API.
diff --git a/src/lib/clients/cache.test.ts b/src/lib/clients/cache.test.ts
index cd0334c81..9d3138d90 100644
--- a/src/lib/clients/cache.test.ts
+++ b/src/lib/clients/cache.test.ts
@@ -1,5 +1,5 @@
 import { describe, test, expect, vi, beforeEach, afterEach } from 'vitest';
-import { Cache } from '$lib/clients/cache';
+import { Cache } from '#lib/clients/cache.js';
 
 describe('Cache', () => {
   // Mock time functions
diff --git a/src/lib/clients/cache_strategy.ts b/src/lib/clients/cache_strategy.ts
index 3b9657536..2a32cd3c7 100644
--- a/src/lib/clients/cache_strategy.ts
+++ b/src/lib/clients/cache_strategy.ts
@@ -1,7 +1,7 @@
-import { Cache } from '$lib/clients/cache';
+import { Cache } from '#lib/clients/cache.js';
 
-import type { ContestsForImport } from '$lib/contests/types/contest';
-import type { TasksForImport } from '$lib/types/task';
+import type { ContestsForImport } from '#lib/contests/types/contest.js';
+import type { TasksForImport } from '#lib/types/task.js';
 
 export class ContestTaskCache {
   constructor(
diff --git a/src/lib/clients/contest_task_fetcher.ts b/src/lib/clients/contest_task_fetcher.ts
index 1310d669c..097d04be7 100644
--- a/src/lib/clients/contest_task_fetcher.ts
+++ b/src/lib/clients/contest_task_fetcher.ts
@@ -1,7 +1,7 @@
-import type { HttpRequestClient } from '$lib/clients/http_client';
-import type { ContestTaskCache } from '$lib/clients/cache_strategy';
-import type { ContestsForImport } from '$lib/contests/types/contest';
-import type { TasksForImport } from '$lib/types/task';
+import type { HttpRequestClient } from '#lib/clients/http_client.js';
+import type { ContestTaskCache } from '#lib/clients/cache_strategy.js';
+import type { ContestsForImport } from '#lib/contests/types/contest.js';
+import type { TasksForImport } from '#lib/types/task.js';
 
 type FetchContestsConfig<T> = {
   cacheKey: string;
diff --git a/src/lib/clients/fixtures/record_requests.ts b/src/lib/clients/fixtures/record_requests.ts
index 25195b053..e45b32022 100644
--- a/src/lib/clients/fixtures/record_requests.ts
+++ b/src/lib/clients/fixtures/record_requests.ts
@@ -1,16 +1,16 @@
 import path from 'path';
 import fs from 'fs';
 
-import { AtCoderProblemsApiClient } from '$lib/clients/atcoder/atcoder_problems';
-import { HttpRequestClient } from '$lib/clients/http_client';
+import { AtCoderProblemsApiClient } from '#lib/clients/atcoder/atcoder_problems.js';
+import { HttpRequestClient } from '#lib/clients/http_client.js';
 
 import type {
   AOJCourseAPI,
   AOJTaskAPIs,
   AOJChallengeContestAPI,
-} from '$lib/clients/aizu_online_judge/types';
+} from '#lib/clients/aizu_online_judge/types.js';
 
-import { AOJ_API_BASE_URL } from '$lib/constants/urls';
+import { AOJ_API_BASE_URL } from '#lib/constants/urls.js';
 
 // Run the main function if you add a contest site.
 // Usage:
diff --git a/src/lib/clients/http_client.ts b/src/lib/clients/http_client.ts
index a01d7bdd0..3617e6d6d 100644
--- a/src/lib/clients/http_client.ts
+++ b/src/lib/clients/http_client.ts
@@ -1,6 +1,6 @@
-import type { ContestsForImport } from '$lib/contests/types/contest';
-import type { TasksForImport } from '$lib/types/task';
-import { delay } from '$lib/utils/time';
+import type { ContestsForImport } from '#lib/contests/types/contest.js';
+import type { TasksForImport } from '#lib/types/task.js';
+import { delay } from '#lib/utils/time.js';
 
 /**
  * Client interface for interacting with tasks and contests API endpoints.
diff --git a/src/lib/clients/index.ts b/src/lib/clients/index.ts
index 5b9c229d2..3bf06520b 100644
--- a/src/lib/clients/index.ts
+++ b/src/lib/clients/index.ts
@@ -1,18 +1,18 @@
-import { HttpRequestClient } from '$lib/clients/http_client';
-import { ContestTaskCache } from '$lib/clients/cache_strategy';
-import { Cache } from '$lib/clients/cache';
+import { HttpRequestClient } from '#lib/clients/http_client.js';
+import { ContestTaskCache } from '#lib/clients/cache_strategy.js';
+import { Cache } from '#lib/clients/cache.js';
 
-import { AtCoderProblemsApiClient } from '$lib/clients/atcoder/atcoder_problems';
+import { AtCoderProblemsApiClient } from '#lib/clients/atcoder/atcoder_problems.js';
 import {
   AojCoursesApiClient,
   AojChallengesApiClient,
-} from '$lib/clients/aizu_online_judge/clients';
+} from '#lib/clients/aizu_online_judge/clients.js';
 
-import type { ContestsForImport } from '$lib/contests/types/contest';
-import type { TasksForImport } from '$lib/types/task';
-import type { ChallengeParams } from '$lib/clients/aizu_online_judge/types';
+import type { ContestsForImport } from '#lib/contests/types/contest.js';
+import type { TasksForImport } from '#lib/types/task.js';
+import type { ChallengeParams } from '#lib/clients/aizu_online_judge/types.js';
 
-import { AOJ_API_BASE_URL } from '$lib/constants/urls';
+import { AOJ_API_BASE_URL } from '#lib/constants/urls.js';
 
 // Supported contest data sources for task import.
 export type ContestTaskImportSource =
diff --git a/src/lib/components/AuthForm.svelte b/src/lib/components/AuthForm.svelte
index b06d72562..2e280efe8 100644
--- a/src/lib/components/AuthForm.svelte
+++ b/src/lib/components/AuthForm.svelte
@@ -10,15 +10,15 @@
   import Eye from '@lucide/svelte/icons/eye';
   import EyeOff from '@lucide/svelte/icons/eye-off';
 
-  import MessageHelperWrapper from '$lib/components/MessageHelperWrapper.svelte';
+  import MessageHelperWrapper from '#lib/components/MessageHelperWrapper.svelte';
 
   import {
     GUEST_USER_NAME,
     GUEST_USER_PASSWORD,
     // GUEST_USER_PASSWORD_FOR_LOCAL,
     LOGIN_LABEL,
-  } from '$lib/constants/forms';
-  import { HOME_PAGE, FORGOT_PASSWORD_PAGE, LOGIN_PAGE } from '$lib/constants/navbar-links';
+  } from '#lib/constants/forms.js';
+  import { HOME_PAGE, FORGOT_PASSWORD_PAGE, LOGIN_PAGE } from '#lib/constants/navbar-links.js';
 
   interface Props {
     // FIXME: 構造体に相当するものを利用した方が拡張・修正がしやすくなるかもしれせまん
diff --git a/src/lib/components/Footer.svelte b/src/lib/components/Footer.svelte
index 28f652d06..94d6a5d2b 100644
--- a/src/lib/components/Footer.svelte
+++ b/src/lib/components/Footer.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
   import { Footer, FooterCopyright } from 'flowbite-svelte';
 
-  import { PRODUCT_TEAM_URL, PRODUCT_NAME } from '$lib/constants/product-info';
+  import { PRODUCT_TEAM_URL, PRODUCT_NAME } from '#lib/constants/product-info.js';
 </script>
 
 <!-- See: -->
diff --git a/src/lib/components/GradeLabel.svelte b/src/lib/components/GradeLabel.svelte
index 04a6f3f5c..029aebefe 100644
--- a/src/lib/components/GradeLabel.svelte
+++ b/src/lib/components/GradeLabel.svelte
@@ -1,11 +1,11 @@
 <script lang="ts">
-  import { TaskGrade } from '$lib/types/task';
+  import { TaskGrade } from '#lib/types/task.js';
   import {
     getTaskGradeColor,
     getTaskGradeLabel,
     toChangeTextColorIfNeeds,
     toChangeBorderColorIfNeeds,
-  } from '$lib/utils/task';
+  } from '#lib/utils/task.js';
 
   interface Props {
     taskGrade: TaskGrade | string;
diff --git a/src/lib/components/Header.svelte b/src/lib/components/Header.svelte
index f06cd41d1..c879c7378 100644
--- a/src/lib/components/Header.svelte
+++ b/src/lib/components/Header.svelte
@@ -17,9 +17,9 @@
   } from 'flowbite-svelte';
   import ChevronDown from '@lucide/svelte/icons/chevron-down';
 
-  import { PRODUCT_NAME } from '$lib/constants/product-info';
-  import { navbarDashboardLinks, navbarLinks } from '$lib/constants/navbar-links';
-  import { externalLinks } from '$lib/constants/external-links';
+  import { PRODUCT_NAME } from '#lib/constants/product-info.js';
+  import { navbarDashboardLinks, navbarLinks } from '#lib/constants/navbar-links.js';
+  import { externalLinks } from '#lib/constants/external-links.js';
 
   let activeUrl = $derived(page.url.pathname);
 
diff --git a/src/lib/components/InputFieldWrapper.svelte b/src/lib/components/InputFieldWrapper.svelte
index 48f6756ac..b45058253 100644
--- a/src/lib/components/InputFieldWrapper.svelte
+++ b/src/lib/components/InputFieldWrapper.svelte
@@ -3,7 +3,7 @@
 
   import { Label, Input } from 'flowbite-svelte';
 
-  import MessageHelperWrapper from '$lib/components/MessageHelperWrapper.svelte';
+  import MessageHelperWrapper from '#lib/components/MessageHelperWrapper.svelte';
 
   // HACK: Use any type out of necessity to maintain compatibility with existing code.
   interface Props {
diff --git a/src/lib/components/LabelWithTooltips.svelte b/src/lib/components/LabelWithTooltips.svelte
index 33a7bc636..a5d29e471 100644
--- a/src/lib/components/LabelWithTooltips.svelte
+++ b/src/lib/components/LabelWithTooltips.svelte
@@ -2,7 +2,7 @@
   import { Label, Tooltip } from 'flowbite-svelte';
   import CircleQuestionMark from '@lucide/svelte/icons/circle-question-mark';
 
-  import { TOOLTIP_CLASS_BASE } from '$lib/constants/tailwind-helper';
+  import { TOOLTIP_CLASS_BASE } from '#lib/constants/tailwind-helper.js';
 
   interface Props {
     labelName: string;
diff --git a/src/lib/components/Messages/ErrorMessageAndReturnButton.svelte b/src/lib/components/Messages/ErrorMessageAndReturnButton.svelte
index dd79fbd31..4f22196ee 100644
--- a/src/lib/components/Messages/ErrorMessageAndReturnButton.svelte
+++ b/src/lib/components/Messages/ErrorMessageAndReturnButton.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
   import { Heading, Button } from 'flowbite-svelte';
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
 
   interface Props {
     errorStatus: number | undefined;
diff --git a/src/lib/components/SubmissionButton.svelte b/src/lib/components/SubmissionButton.svelte
index e48d2d66c..d1ea3a224 100644
--- a/src/lib/components/SubmissionButton.svelte
+++ b/src/lib/components/SubmissionButton.svelte
@@ -2,7 +2,7 @@
   import { getContext } from 'svelte';
 
   import { Button } from 'flowbite-svelte';
-  import type { ButtonColor } from '$lib/types/flowbite-svelte-wrapper';
+  import type { ButtonColor } from '#lib/types/flowbite-svelte-wrapper.js';
 
   interface Props {
     width?: string;
diff --git a/src/lib/components/SubmissionStatus/SubmissionStatusImage.svelte b/src/lib/components/SubmissionStatus/SubmissionStatusImage.svelte
index 76333e2ff..6a9277786 100644
--- a/src/lib/components/SubmissionStatus/SubmissionStatusImage.svelte
+++ b/src/lib/components/SubmissionStatus/SubmissionStatusImage.svelte
@@ -2,7 +2,7 @@
   import { Img } from 'flowbite-svelte';
   import ChevronDown from '@lucide/svelte/icons/chevron-down';
 
-  import type { TaskResult } from '$lib/types/task';
+  import type { TaskResult } from '#lib/types/task.js';
 
   interface Props {
     taskResult: TaskResult;
diff --git a/src/lib/components/SubmissionStatus/UpdatingDropdown.svelte b/src/lib/components/SubmissionStatus/UpdatingDropdown.svelte
index d8e5dfd2b..30f6804be 100644
--- a/src/lib/components/SubmissionStatus/UpdatingDropdown.svelte
+++ b/src/lib/components/SubmissionStatus/UpdatingDropdown.svelte
@@ -1,9 +1,9 @@
 <!-- Usage
 // Script
 <script lang="ts">
-  import type { TaskResult } from '$lib/types/task';
+  import type { TaskResult } from '#lib/types/task.js';
 
-  import UpdatingDropdown from '$lib/components/SubmissionStatus/UpdatingDropdown.svelte';
+  import UpdatingDropdown from '#lib/components/SubmissionStatus/UpdatingDropdown.svelte';
 
   interface Props {
     taskResult: TaskResult;
@@ -26,12 +26,12 @@
   import Check from '@lucide/svelte/icons/check';
   import ChevronDown from '@lucide/svelte/icons/chevron-down';
 
-  import type { TaskResult } from '$lib/types/task';
+  import type { TaskResult } from '#lib/types/task.js';
 
-  import InputFieldWrapper from '$lib/components/InputFieldWrapper.svelte';
+  import InputFieldWrapper from '#lib/components/InputFieldWrapper.svelte';
 
-  import { submission_statuses } from '$lib/services/submission_status';
-  import { errorMessageStore } from '$lib/stores/error_message';
+  import { submission_statuses } from '#lib/services/submission_status.js';
+  import { errorMessageStore } from '#lib/stores/error_message.js';
 
   import { buildLoginPath } from '$features/auth/utils/login';
   import { buildSignupPath } from '$features/auth/utils/signup';
diff --git a/src/lib/components/SubmissionStatus/UpdatingModal.svelte b/src/lib/components/SubmissionStatus/UpdatingModal.svelte
index e5def16c7..5bde3b4b6 100644
--- a/src/lib/components/SubmissionStatus/UpdatingModal.svelte
+++ b/src/lib/components/SubmissionStatus/UpdatingModal.svelte
@@ -3,13 +3,13 @@
 
   import { Button, Modal, Select } from 'flowbite-svelte';
 
-  import type { TaskResult } from '$lib/types/task';
+  import type { TaskResult } from '#lib/types/task.js';
 
-  import { submission_statuses } from '$lib/services/submission_status';
-  import { errorMessageStore } from '$lib/stores/error_message';
+  import { submission_statuses } from '#lib/services/submission_status.js';
+  import { errorMessageStore } from '#lib/stores/error_message.js';
 
-  import { getContestNameLabel } from '$lib/contests';
-  import InputFieldWrapper from '$lib/components/InputFieldWrapper.svelte';
+  import { getContestNameLabel } from '#lib/contests/index.js';
+  import InputFieldWrapper from '#lib/components/InputFieldWrapper.svelte';
 
   interface Props {
     isLoggedIn: boolean;
diff --git a/src/lib/components/Tabs/ProblemListTabItem.svelte b/src/lib/components/Tabs/ProblemListTabItem.svelte
index 6deadc3f6..65d46ce11 100644
--- a/src/lib/components/Tabs/ProblemListTabItem.svelte
+++ b/src/lib/components/Tabs/ProblemListTabItem.svelte
@@ -6,7 +6,7 @@
   import {
     activeProblemListTabStore,
     type ActiveProblemListTab,
-  } from '$lib/stores/active_problem_list_tab.svelte';
+  } from '#lib/stores/active_problem_list_tab.svelte.js';
 
   interface Props {
     activeProblemList: ActiveProblemListTab;
diff --git a/src/lib/components/Tabs/TabItemWrapper.svelte b/src/lib/components/Tabs/TabItemWrapper.svelte
index f6c7972de..f76ff9fe9 100644
--- a/src/lib/components/Tabs/TabItemWrapper.svelte
+++ b/src/lib/components/Tabs/TabItemWrapper.svelte
@@ -4,7 +4,7 @@
   import { TabItem, Tooltip } from 'flowbite-svelte';
   import CircleQuestionMark from '@lucide/svelte/icons/circle-question-mark';
 
-  import { TOOLTIP_CLASS_BASE } from '$lib/constants/tailwind-helper';
+  import { TOOLTIP_CLASS_BASE } from '#lib/constants/tailwind-helper.js';
 
   interface Props {
     isOpen?: boolean;
diff --git a/src/lib/components/TagForm.svelte b/src/lib/components/TagForm.svelte
index 177b62c2d..582111585 100644
--- a/src/lib/components/TagForm.svelte
+++ b/src/lib/components/TagForm.svelte
@@ -11,11 +11,11 @@
     TableHead,
     TableHeadCell,
   } from 'flowbite-svelte';
-  import type { Task } from '$lib/types/task';
-  import type { Tag } from '$lib/types/tag';
+  import type { Task } from '#lib/types/task.js';
+  import type { Tag } from '#lib/types/tag.js';
 
-  import { getContestNameLabel } from '$lib/contests';
-  import { ATCODER_BASE_CONTEST_URL } from '$lib/constants/urls';
+  import { getContestNameLabel } from '#lib/contests/index.js';
+  import { ATCODER_BASE_CONTEST_URL } from '#lib/constants/urls.js';
 
   interface Props {
     tag: Tag;
diff --git a/src/lib/components/TagListForEdit.svelte b/src/lib/components/TagListForEdit.svelte
index 53bc907e3..d76860f1b 100644
--- a/src/lib/components/TagListForEdit.svelte
+++ b/src/lib/components/TagListForEdit.svelte
@@ -10,10 +10,10 @@
     TableHeadCell,
     Label,
   } from 'flowbite-svelte';
-  import type { Tag } from '$lib/types/tag';
-  //import { ATCODER_BASE_CONTEST_URL } from '$lib/constants/urls';
+  import type { Tag } from '#lib/types/tag.js';
+  //import { ATCODER_BASE_CONTEST_URL } from '#lib/constants/urls.js';
 
-  import { newline } from '$lib/utils/newline';
+  import { newline } from '#lib/utils/newline.js';
 
   //gradeでソート済みのTaskのリストと、APIから取得したtasklistを表示する
   //xport let tasks: Task[];
diff --git a/src/lib/components/TaskForm.svelte b/src/lib/components/TaskForm.svelte
index 5eb7993f9..5fee48d96 100644
--- a/src/lib/components/TaskForm.svelte
+++ b/src/lib/components/TaskForm.svelte
@@ -10,9 +10,9 @@
     Label,
     Button,
   } from 'flowbite-svelte';
-  import { addContestNameToTaskIndex } from '$lib/contests';
-  import { taskGradeValues, type Task } from '$lib/types/task';
-  import { getTaskGradeLabel, removeTaskIndexFromTitle } from '$lib/utils/task';
+  import { addContestNameToTaskIndex } from '#lib/contests/index.js';
+  import { taskGradeValues, type Task } from '#lib/types/task.js';
+  import { getTaskGradeLabel, removeTaskIndexFromTitle } from '#lib/utils/task.js';
 
   interface Props {
     task: Task;
diff --git a/src/lib/components/TaskGradeList.svelte b/src/lib/components/TaskGradeList.svelte
index dadfbb9c1..4423d3b53 100644
--- a/src/lib/components/TaskGradeList.svelte
+++ b/src/lib/components/TaskGradeList.svelte
@@ -1,8 +1,8 @@
 <script lang="ts">
-  import TaskList from '$lib/components/TaskList.svelte';
+  import TaskList from '#lib/components/TaskList.svelte';
 
-  import type { TaskResults, TaskResult } from '$lib/types/task';
-  import { TaskGrade, taskGradeValues } from '$lib/types/task';
+  import type { TaskResults, TaskResult } from '#lib/types/task.js';
+  import { TaskGrade, taskGradeValues } from '#lib/types/task.js';
 
   interface Props {
     taskResults: TaskResults;
diff --git a/src/lib/components/TaskGrades/GradeGuidelineTable.svelte b/src/lib/components/TaskGrades/GradeGuidelineTable.svelte
index 864cca47e..f5b823c01 100644
--- a/src/lib/components/TaskGrades/GradeGuidelineTable.svelte
+++ b/src/lib/components/TaskGrades/GradeGuidelineTable.svelte
@@ -7,11 +7,11 @@
     TableHead,
     TableHeadCell,
   } from 'flowbite-svelte';
-  import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
-  import { gradeGuidelineTableData } from '$lib/components/TaskGrades/grade_guideline_table_data';
-  import GradeLabel from '$lib/components/GradeLabel.svelte';
+  import ExternalLinkWrapper from '#lib/components/ExternalLinkWrapper.svelte';
+  import { gradeGuidelineTableData } from '#lib/components/TaskGrades/grade_guideline_table_data.js';
+  import GradeLabel from '#lib/components/GradeLabel.svelte';
 
-  import { TASK_GRADE_CRITERIA_SHEET_URL } from '$lib/constants/urls';
+  import { TASK_GRADE_CRITERIA_SHEET_URL } from '#lib/constants/urls.js';
 </script>
 
 <div class="container mx-auto w-5/6 lg:w-2/3 mt-4 text-gray-800 dark:text-gray-300">
diff --git a/src/lib/components/TaskGrades/grade_guideline_table_data.ts b/src/lib/components/TaskGrades/grade_guideline_table_data.ts
index 6d40a9050..7d5dd1d3c 100644
--- a/src/lib/components/TaskGrades/grade_guideline_table_data.ts
+++ b/src/lib/components/TaskGrades/grade_guideline_table_data.ts
@@ -1,4 +1,4 @@
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 
 type TaskGradeGuideline = {
   point: string;
diff --git a/src/lib/components/TaskList.svelte b/src/lib/components/TaskList.svelte
index b8174ef6a..79d5d4ea7 100644
--- a/src/lib/components/TaskList.svelte
+++ b/src/lib/components/TaskList.svelte
@@ -10,24 +10,24 @@
     TableHeadCell,
   } from 'flowbite-svelte';
 
-  import { type TaskResult, type TaskResults } from '$lib/types/task';
+  import { type TaskResult, type TaskResults } from '#lib/types/task.js';
 
-  import GradeLabel from '$lib/components/GradeLabel.svelte';
-  import ThermometerProgressBar from '$lib/components/ThermometerProgressBar.svelte';
-  import UpdatingModal from '$lib/components/SubmissionStatus/UpdatingModal.svelte';
-  import SubmissionStatusImage from '$lib/components/SubmissionStatus/SubmissionStatusImage.svelte';
-  import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
-  import AcceptedCounter from '$lib/components/SubmissionStatus/AcceptedCounter.svelte';
+  import GradeLabel from '#lib/components/GradeLabel.svelte';
+  import ThermometerProgressBar from '#lib/components/ThermometerProgressBar.svelte';
+  import UpdatingModal from '#lib/components/SubmissionStatus/UpdatingModal.svelte';
+  import SubmissionStatusImage from '#lib/components/SubmissionStatus/SubmissionStatusImage.svelte';
+  import ExternalLinkWrapper from '#lib/components/ExternalLinkWrapper.svelte';
+  import AcceptedCounter from '#lib/components/SubmissionStatus/AcceptedCounter.svelte';
 
-  import { getBackgroundColorFrom } from '$lib/services/submission_status';
+  import { getBackgroundColorFrom } from '#lib/services/submission_status.js';
 
-  import { addContestNameToTaskIndex } from '$lib/contests';
+  import { addContestNameToTaskIndex } from '#lib/contests/index.js';
   import {
     countAcceptedTasks,
     countAllTasks,
     getTaskUrl,
     removeTaskIndexFromTitle,
-  } from '$lib/utils/task';
+  } from '#lib/utils/task.js';
 
   interface Props {
     grade: string;
diff --git a/src/lib/components/TaskListSorted.svelte b/src/lib/components/TaskListSorted.svelte
index a58be92ab..1c257b500 100644
--- a/src/lib/components/TaskListSorted.svelte
+++ b/src/lib/components/TaskListSorted.svelte
@@ -10,10 +10,10 @@
     TableHead,
     TableHeadCell,
   } from 'flowbite-svelte';
-  import type { TaskResults } from '$lib/types/task';
+  import type { TaskResults } from '#lib/types/task.js';
 
-  import { addContestNameToTaskIndex } from '$lib/contests';
-  import { removeTaskIndexFromTitle } from '$lib/utils/task';
+  import { addContestNameToTaskIndex } from '#lib/contests/index.js';
+  import { removeTaskIndexFromTitle } from '#lib/utils/task.js';
 
   interface Props {
     taskResults: TaskResults;
diff --git a/src/lib/components/TaskSearchBox.svelte b/src/lib/components/TaskSearchBox.svelte
index 21651585e..fc5d3d875 100644
--- a/src/lib/components/TaskSearchBox.svelte
+++ b/src/lib/components/TaskSearchBox.svelte
@@ -3,18 +3,18 @@
 <script lang="ts">
   import { Input, Listgroup } from 'flowbite-svelte';
 
-  import SelectWrapper from '$lib/components/SelectWrapper.svelte';
-  import LabelWithTooltips from '$lib/components/LabelWithTooltips.svelte';
-  import GradeLabel from '$lib/components/GradeLabel.svelte';
+  import SelectWrapper from '#lib/components/SelectWrapper.svelte';
+  import LabelWithTooltips from '#lib/components/LabelWithTooltips.svelte';
+  import GradeLabel from '#lib/components/GradeLabel.svelte';
 
-  import type { Task, Tasks } from '$lib/types/task';
+  import type { Task, Tasks } from '#lib/types/task.js';
   import type {
     WorkBookTasksBase,
     WorkBookTasksCreate,
     WorkBookTasksEdit,
   } from '$features/workbooks/types/workbook';
 
-  import { getTaskUrl } from '$lib/utils/task';
+  import { getTaskUrl } from '#lib/utils/task.js';
   import {
     generateWorkBookTaskOrders,
     addTaskToWorkBook,
diff --git a/src/lib/components/ThermometerProgressBar.svelte b/src/lib/components/ThermometerProgressBar.svelte
index 9d8251e33..17c4be347 100644
--- a/src/lib/components/ThermometerProgressBar.svelte
+++ b/src/lib/components/ThermometerProgressBar.svelte
@@ -1,13 +1,13 @@
 <script lang="ts">
   import { Tooltip } from 'flowbite-svelte';
 
-  import type { TaskResult, TaskResults } from '$lib/types/task';
-  import type { SubmissionRatios, SubmissionCounts } from '$lib/types/submission';
+  import type { TaskResult, TaskResults } from '#lib/types/task.js';
+  import type { SubmissionRatios, SubmissionCounts } from '#lib/types/submission.js';
   import type { WorkBookTaskBase } from '$features/workbooks/types/workbook';
 
-  import { submission_statuses } from '$lib/services/submission_status';
+  import { submission_statuses } from '#lib/services/submission_status.js';
 
-  import { TOOLTIP_CLASS_BASE } from '$lib/constants/tailwind-helper';
+  import { TOOLTIP_CLASS_BASE } from '#lib/constants/tailwind-helper.js';
 
   interface Props {
     workBookTasks?: WorkBookTaskBase[];
diff --git a/src/lib/components/TooltipWrapper.svelte b/src/lib/components/TooltipWrapper.svelte
index d7d2ab89f..06877e82b 100644
--- a/src/lib/components/TooltipWrapper.svelte
+++ b/src/lib/components/TooltipWrapper.svelte
@@ -4,7 +4,7 @@
   import { Tooltip } from 'flowbite-svelte';
   import CircleQuestionMark from '@lucide/svelte/icons/circle-question-mark';
 
-  import { TOOLTIP_CLASS_BASE } from '$lib/constants/tailwind-helper';
+  import { TOOLTIP_CLASS_BASE } from '#lib/constants/tailwind-helper.js';
 
   interface Props {
     tooltipContent?: string;
diff --git a/src/lib/components/Trophies/CompletedTasks.svelte b/src/lib/components/Trophies/CompletedTasks.svelte
index e6ae7c417..fd4fc57bf 100644
--- a/src/lib/components/Trophies/CompletedTasks.svelte
+++ b/src/lib/components/Trophies/CompletedTasks.svelte
@@ -1,10 +1,10 @@
 <script lang="ts">
   import { Img } from 'flowbite-svelte';
 
-  import type { TaskResults } from '$lib/types/task';
+  import type { TaskResults } from '#lib/types/task.js';
   import type { WorkBookTaskBase } from '$features/workbooks/types/workbook';
 
-  import { areAllTasksAccepted } from '$lib/utils/task';
+  import { areAllTasksAccepted } from '#lib/utils/task.js';
 
   /**
    * Props for the CompletedTasks component
diff --git a/src/lib/contests/fixtures/contest_name_and_task_index.ts b/src/lib/contests/fixtures/contest_name_and_task_index.ts
index b25f6518a..51e81dcfd 100644
--- a/src/lib/contests/fixtures/contest_name_and_task_index.ts
+++ b/src/lib/contests/fixtures/contest_name_and_task_index.ts
@@ -6,7 +6,7 @@ import {
   getAojContestLabel,
   PAST_TRANSLATIONS,
   AOJ_COURSES,
-} from '$lib/contests';
+} from '#lib/contests/index.js';
 
 export type TestCaseForContestNameAndTaskIndex = {
   contestId: string;
diff --git a/src/lib/contests/fixtures/contest_type.ts b/src/lib/contests/fixtures/contest_type.ts
index 8c2cc093c..cd5131ca9 100644
--- a/src/lib/contests/fixtures/contest_type.ts
+++ b/src/lib/contests/fixtures/contest_type.ts
@@ -1,5 +1,5 @@
 import { createTestCase } from '../../../test/lib/common/test_helpers';
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 
 export type TestCaseForContestType = {
   contestId: string;
diff --git a/src/lib/contests/types/contest.ts b/src/lib/contests/types/contest.ts
index de3fb54b6..affde19ee 100644
--- a/src/lib/contests/types/contest.ts
+++ b/src/lib/contests/types/contest.ts
@@ -1,4 +1,4 @@
-import type { TasksForImport } from '$lib/types/task';
+import type { TasksForImport } from '#lib/types/task.js';
 
 export interface Contest {
   id: string;
diff --git a/src/lib/contests/utils/classification.test.ts b/src/lib/contests/utils/classification.test.ts
index 32e8cd565..9901b35fb 100644
--- a/src/lib/contests/utils/classification.test.ts
+++ b/src/lib/contests/utils/classification.test.ts
@@ -1,10 +1,10 @@
 import { expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 import { runTests } from '../../../test/lib/common/test_helpers';
-import * as TestCasesForContestType from '$lib/contests/fixtures/contest_type';
-import { type TestCaseForContestType } from '$lib/contests/fixtures/contest_type';
-import { classifyContest } from '$lib/contests/utils/classification';
+import * as TestCasesForContestType from '#lib/contests/fixtures/contest_type.js';
+import { type TestCaseForContestType } from '#lib/contests/fixtures/contest_type.js';
+import { classifyContest } from '#lib/contests/utils/classification.js';
 
 describe('classify contest', () => {
   describe('AtCoder', () => {
diff --git a/src/lib/contests/utils/classification.ts b/src/lib/contests/utils/classification.ts
index be87a8ed3..7fa0786fe 100644
--- a/src/lib/contests/utils/classification.ts
+++ b/src/lib/contests/utils/classification.ts
@@ -1,4 +1,4 @@
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 import {
   regexForJag,
   regexForAojUniversity,
diff --git a/src/lib/contests/utils/labels/aoj.test.ts b/src/lib/contests/utils/labels/aoj.test.ts
index 9722362b8..424443233 100644
--- a/src/lib/contests/utils/labels/aoj.test.ts
+++ b/src/lib/contests/utils/labels/aoj.test.ts
@@ -1,13 +1,13 @@
 import { expect } from 'vitest';
 
-import { AOJ_COURSES } from '$lib/contests/utils/prefixes';
+import { AOJ_COURSES } from '#lib/contests/utils/prefixes.js';
 import {
   getAojContestLabel,
   getAojUniversityContestLabel,
   PCK_TRANSLATIONS,
   JAG_TRANSLATIONS,
   ICPC_TRANSLATIONS,
-} from '$lib/contests/utils/labels/aoj';
+} from '#lib/contests/utils/labels/aoj.js';
 
 describe('get AOJ contest label', () => {
   describe('AOJ courses', () => {
diff --git a/src/lib/contests/utils/labels/aoj.ts b/src/lib/contests/utils/labels/aoj.ts
index 9cf3165a6..e2dc22fe7 100644
--- a/src/lib/contests/utils/labels/aoj.ts
+++ b/src/lib/contests/utils/labels/aoj.ts
@@ -1,4 +1,4 @@
-import type { ContestLabelTranslations } from '$lib/contests/types/contest';
+import type { ContestLabelTranslations } from '#lib/contests/types/contest.js';
 
 /**
  * Maps PCK contest type abbreviations to their Japanese translations.
diff --git a/src/lib/contests/utils/labels/atcoder_others.test.ts b/src/lib/contests/utils/labels/atcoder_others.test.ts
index 80109f882..6b789fd63 100644
--- a/src/lib/contests/utils/labels/atcoder_others.test.ts
+++ b/src/lib/contests/utils/labels/atcoder_others.test.ts
@@ -1,6 +1,6 @@
 import { expect } from 'vitest';
 
-import { generateOthersLabel } from '$lib/contests/utils/labels/atcoder_others';
+import { generateOthersLabel } from '#lib/contests/utils/labels/atcoder_others.js';
 
 describe('generate AtCoder others label', () => {
   describe('when the contest_id matches the AxC pattern', () => {
diff --git a/src/lib/contests/utils/labels/axc.test.ts b/src/lib/contests/utils/labels/axc.test.ts
index 390e1ca2d..fc273ecb1 100644
--- a/src/lib/contests/utils/labels/axc.test.ts
+++ b/src/lib/contests/utils/labels/axc.test.ts
@@ -1,6 +1,6 @@
 import { expect } from 'vitest';
 
-import { generateAxcLabel, generateAwcLabel } from '$lib/contests/utils/labels/axc';
+import { generateAxcLabel, generateAwcLabel } from '#lib/contests/utils/labels/axc.js';
 
 describe('generate AxC label', () => {
   describe('when a three-digit contest_id is given', () => {
diff --git a/src/lib/contests/utils/labels/index.test.ts b/src/lib/contests/utils/labels/index.test.ts
index e881fcebe..5366b0dc0 100644
--- a/src/lib/contests/utils/labels/index.test.ts
+++ b/src/lib/contests/utils/labels/index.test.ts
@@ -1,10 +1,10 @@
 import { expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 import { runTests } from '../../../../test/lib/common/test_helpers';
-import * as TestCasesForContestNameLabel from '$lib/contests/fixtures/contest_name_labels';
-import { type TestCaseForContestNameLabel } from '$lib/contests/fixtures/contest_name_labels';
-import { getContestNameLabel, LABEL_GENERATORS } from '$lib/contests/utils/labels/index';
+import * as TestCasesForContestNameLabel from '#lib/contests/fixtures/contest_name_labels.js';
+import { type TestCaseForContestNameLabel } from '#lib/contests/fixtures/contest_name_labels.js';
+import { getContestNameLabel, LABEL_GENERATORS } from '#lib/contests/utils/labels/index.js';
 
 /**
  * Contest types that classifyContest can return but LABEL_GENERATORS deliberately
diff --git a/src/lib/contests/utils/labels/index.ts b/src/lib/contests/utils/labels/index.ts
index 94c16920d..8de8f0554 100644
--- a/src/lib/contests/utils/labels/index.ts
+++ b/src/lib/contests/utils/labels/index.ts
@@ -1,4 +1,4 @@
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 
 import { classifyContest } from '../classification';
 import { AOJ_COURSES, ATCODER_MAIN_OFFICIAL_ONSITE } from '../prefixes';
diff --git a/src/lib/contests/utils/labels/joi.test.ts b/src/lib/contests/utils/labels/joi.test.ts
index 93b00f4e7..be74a571c 100644
--- a/src/lib/contests/utils/labels/joi.test.ts
+++ b/src/lib/contests/utils/labels/joi.test.ts
@@ -1,6 +1,6 @@
 import { expect } from 'vitest';
 
-import { getJoiContestLabel } from '$lib/contests/utils/labels/joi';
+import { getJoiContestLabel } from '#lib/contests/utils/labels/joi.js';
 
 describe('get JOI contest label', () => {
   describe('qualifying rounds', () => {
diff --git a/src/lib/contests/utils/labels/past.test.ts b/src/lib/contests/utils/labels/past.test.ts
index e36ed6bbb..5b13d1880 100644
--- a/src/lib/contests/utils/labels/past.test.ts
+++ b/src/lib/contests/utils/labels/past.test.ts
@@ -1,6 +1,6 @@
 import { expect } from 'vitest';
 
-import { getPastContestLabel, PAST_TRANSLATIONS } from '$lib/contests/utils/labels/past';
+import { getPastContestLabel, PAST_TRANSLATIONS } from '#lib/contests/utils/labels/past.js';
 
 describe('get PAST contest label', () => {
   describe('contests identified by year and month (1st to 14th)', () => {
diff --git a/src/lib/contests/utils/labels/past.ts b/src/lib/contests/utils/labels/past.ts
index 45ff9e968..fd0fb550b 100644
--- a/src/lib/contests/utils/labels/past.ts
+++ b/src/lib/contests/utils/labels/past.ts
@@ -1,4 +1,4 @@
-import type { ContestLabelTranslations } from '$lib/contests/types/contest';
+import type { ContestLabelTranslations } from '#lib/contests/types/contest.js';
 
 /**
  * A mapping of contest dates to their respective Japanese translations.
diff --git a/src/lib/contests/utils/labels/universities.test.ts b/src/lib/contests/utils/labels/universities.test.ts
index ed13e1519..0da1f401d 100644
--- a/src/lib/contests/utils/labels/universities.test.ts
+++ b/src/lib/contests/utils/labels/universities.test.ts
@@ -1,6 +1,6 @@
 import { expect } from 'vitest';
 
-import { getAtCoderUniversityContestLabel } from '$lib/contests/utils/labels/universities';
+import { getAtCoderUniversityContestLabel } from '#lib/contests/utils/labels/universities.js';
 
 describe('get AtCoder university contest label', () => {
   describe('expected to return correct label for valid format', () => {
diff --git a/src/lib/contests/utils/prefixes.ts b/src/lib/contests/utils/prefixes.ts
index 6a0fcb16b..0c476ee00 100644
--- a/src/lib/contests/utils/prefixes.ts
+++ b/src/lib/contests/utils/prefixes.ts
@@ -1,4 +1,4 @@
-import type { ContestPrefix } from '$lib/contests/types/contest';
+import type { ContestPrefix } from '#lib/contests/types/contest.js';
 
 export const regexForJag = /^JAG(Prelim|Regional|Summer|Winter|Spring)\d{4}(-day\d+)?[A-Z]?$/;
 export const regexForAojUniversity = /^AOJ-[A-Z]+PC\d{4}/;
diff --git a/src/lib/contests/utils/priority.test.ts b/src/lib/contests/utils/priority.test.ts
index 2e088f0dc..4db62d293 100644
--- a/src/lib/contests/utils/priority.test.ts
+++ b/src/lib/contests/utils/priority.test.ts
@@ -1,11 +1,11 @@
 import { expect } from 'vitest';
 
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 import {
   getContestPriority,
   contestTypePriorities,
   UNCLASSIFIED_CONTEST_PRIORITY,
-} from '$lib/contests/utils/priority';
+} from '#lib/contests/utils/priority.js';
 
 /** One representative contest_id per category, listed from highest to lowest priority. */
 const contestIdsInDisplayOrder = [
diff --git a/src/lib/contests/utils/priority.ts b/src/lib/contests/utils/priority.ts
index 878498b40..1d8883d72 100644
--- a/src/lib/contests/utils/priority.ts
+++ b/src/lib/contests/utils/priority.ts
@@ -1,4 +1,4 @@
-import { ContestType } from '$lib/contests/types/contest';
+import { ContestType } from '#lib/contests/types/contest.js';
 import { classifyContest } from './classification';
 
 /**
diff --git a/src/lib/contests/utils/task_index_label.test.ts b/src/lib/contests/utils/task_index_label.test.ts
index 7a00ef12c..d690ac565 100644
--- a/src/lib/contests/utils/task_index_label.test.ts
+++ b/src/lib/contests/utils/task_index_label.test.ts
@@ -1,9 +1,9 @@
 import { expect } from 'vitest';
 
 import { runTests } from '../../../test/lib/common/test_helpers';
-import * as TestCasesForContestNameAndTaskIndex from '$lib/contests/fixtures/contest_name_and_task_index';
-import { type TestCaseForContestNameAndTaskIndex } from '$lib/contests/fixtures/contest_name_and_task_index';
-import { addContestNameToTaskIndex } from '$lib/contests/utils/task_index_label';
+import * as TestCasesForContestNameAndTaskIndex from '#lib/contests/fixtures/contest_name_and_task_index.js';
+import { type TestCaseForContestNameAndTaskIndex } from '#lib/contests/fixtures/contest_name_and_task_index.js';
+import { addContestNameToTaskIndex } from '#lib/contests/utils/task_index_label.js';
 
 describe('add contest name to task index', () => {
   describe('AtCoder', () => {
diff --git a/src/lib/server/tasks/cache.test.ts b/src/lib/server/tasks/cache.test.ts
index 5c687df88..63343d1f5 100644
--- a/src/lib/server/tasks/cache.test.ts
+++ b/src/lib/server/tasks/cache.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect, vi, beforeEach, afterEach, afterAll } from 'vitest';
 
-import type { Task } from '$lib/types/task';
+import type { Task } from '#lib/types/task.js';
 import {
   getCachedTasksMap,
   getCachedMergedTasksMap,
diff --git a/src/lib/server/tasks/cache.ts b/src/lib/server/tasks/cache.ts
index ef676a749..1a1c0891b 100644
--- a/src/lib/server/tasks/cache.ts
+++ b/src/lib/server/tasks/cache.ts
@@ -1,7 +1,7 @@
-import type { Task } from '$lib/types/task';
-import type { TaskMapByContestTaskPair } from '$lib/types/contest_task_pair';
+import type { Task } from '#lib/types/task.js';
+import type { TaskMapByContestTaskPair } from '#lib/types/contest_task_pair.js';
 
-import { Cache, DEFAULT_CACHE_TTL } from '$lib/clients/cache';
+import { Cache, DEFAULT_CACHE_TTL } from '#lib/clients/cache.js';
 
 const TASK_MAP_KEY = 'tasks_by_task_id';
 const MERGED_KEY = 'merged_tasks_map';
diff --git a/src/lib/services/answers.ts b/src/lib/services/answers.ts
index 6905e906c..df63368a8 100644
--- a/src/lib/services/answers.ts
+++ b/src/lib/services/answers.ts
@@ -1,8 +1,8 @@
 import { initialize } from '@quramy/prisma-fabbrica/lib/internal';
 
-import { default as prisma } from '$lib/server/database';
+import { default as prisma } from '#lib/server/database.js';
 import type { TaskAnswer } from '@prisma/client';
-import { sha256 } from '$lib/utils/hash';
+import { sha256 } from '#lib/utils/hash.js';
 
 initialize({ prisma });
 
diff --git a/src/lib/services/contest_task_pairs.ts b/src/lib/services/contest_task_pairs.ts
index c9c23a7e9..8cdf42c71 100644
--- a/src/lib/services/contest_task_pairs.ts
+++ b/src/lib/services/contest_task_pairs.ts
@@ -1,13 +1,13 @@
 import { Prisma } from '@prisma/client';
 
-import { default as db } from '$lib/server/database';
+import { default as db } from '#lib/server/database.js';
 
 import type {
   ContestTaskPair,
   ContestTaskPairs,
   ContestTaskPairCreate,
   ContestTaskPairUpdate,
-} from '$lib/types/contest_task_pair';
+} from '#lib/types/contest_task_pair.js';
 
 /**
  * Retrieves all ContestTaskPair records from the database.
diff --git a/src/lib/services/submission_status.ts b/src/lib/services/submission_status.ts
index dfb3f8181..6dd7fd0d9 100644
--- a/src/lib/services/submission_status.ts
+++ b/src/lib/services/submission_status.ts
@@ -1,4 +1,4 @@
-//import client from '$lib/server/database';
+//import client from '#lib/server/database.js';
 
 // CI: 提出状況に関するCRUDを実行する部分で原因不明のビルドエラーが発生する
 // 現時点での対処方法: 暫定的にベタ打ちの値を使用
diff --git a/src/lib/services/tags.test.ts b/src/lib/services/tags.test.ts
index d4f4e26ef..18a424319 100644
--- a/src/lib/services/tags.test.ts
+++ b/src/lib/services/tags.test.ts
@@ -1,8 +1,8 @@
 import { describe, test, expect, vi } from 'vitest';
 
-import { getTag } from '$lib/services/tags';
+import { getTag } from '#lib/services/tags.js';
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     tag: {
       findUnique: vi.fn(),
@@ -10,7 +10,7 @@ vi.mock('$lib/server/database', () => ({
   },
 }));
 
-import db from '$lib/server/database';
+import db from '#lib/server/database.js';
 
 describe('getTag', () => {
   const mockDb = db as unknown as { tag: { findUnique: ReturnType<typeof vi.fn> } };
diff --git a/src/lib/services/tags.ts b/src/lib/services/tags.ts
index d2d0ff6e5..46e376cc9 100644
--- a/src/lib/services/tags.ts
+++ b/src/lib/services/tags.ts
@@ -1,5 +1,5 @@
-import { default as db } from '$lib/server/database';
-import type { Tag } from '$lib/types/tag';
+import { default as db } from '#lib/server/database.js';
+import type { Tag } from '#lib/types/tag.js';
 
 // See:
 // https://www.prisma.io/docs/concepts/components/prisma-client/filtering-and-sorting
diff --git a/src/lib/services/task_results.ts b/src/lib/services/task_results.ts
index cce4582d5..6737f730d 100644
--- a/src/lib/services/task_results.ts
+++ b/src/lib/services/task_results.ts
@@ -1,32 +1,32 @@
 import { error } from '@sveltejs/kit';
 
-import { default as db } from '$lib/server/database';
+import { default as db } from '#lib/server/database.js';
 import {
   getTasks,
   getMergedTasksMap,
   getTasksWithSelectedTaskIds,
   getTask,
-} from '$lib/services/tasks';
+} from '#lib/services/tasks.js';
 import {
   getSubmissionStatusMapWithId,
   getSubmissionStatusMapWithName,
-} from '$lib/services/submission_status';
-import { getUser } from '$lib/services/users';
-import * as answer_crud from '$lib/services/answers';
+} from '#lib/services/submission_status.js';
+import { getUser } from '#lib/services/users.js';
+import * as answer_crud from '#lib/services/answers.js';
 
 import {
   validateUserAnswersTransferability,
   isExistingUser,
   isSameUser,
-} from '$lib/utils/account_transfer';
+} from '#lib/utils/account_transfer.js';
 
 import type { User } from '@prisma/client';
-import type { TaskResult, TaskResults, Task, Tasks } from '$lib/types/task';
-import type { TaskAnswer } from '$lib/types/answer';
-import type { FloatingMessages } from '$lib/types/floating_message';
+import type { TaskResult, TaskResults, Task, Tasks } from '#lib/types/task.js';
+import type { TaskAnswer } from '#lib/types/answer.js';
+import type { FloatingMessages } from '#lib/types/floating_message.js';
 import type { WorkBookTasksBase } from '$features/workbooks/types/workbook';
 
-import { NOT_FOUND } from '$lib/constants/http-response-status-codes';
+import { NOT_FOUND } from '#lib/constants/http-response-status-codes.js';
 
 // DBから取得した問題とログインしているユーザの回答を紐付けしたデータ保持
 const statusById = await getSubmissionStatusMapWithId();
diff --git a/src/lib/services/task_tags.ts b/src/lib/services/task_tags.ts
index 4ee74071c..ede16abcc 100644
--- a/src/lib/services/task_tags.ts
+++ b/src/lib/services/task_tags.ts
@@ -1,6 +1,6 @@
-import { default as db } from '$lib/server/database';
-import type { Task } from '$lib/types/task';
-import type { Tag } from '$lib/types/tag';
+import { default as db } from '#lib/server/database.js';
+import type { Task } from '#lib/types/task.js';
+import type { Tag } from '#lib/types/tag.js';
 // See:
 // https://www.prisma.io/docs/concepts/components/prisma-client/filtering-and-sorting
 export async function getTasks(tag_id: string) {
diff --git a/src/lib/services/tasks.ts b/src/lib/services/tasks.ts
index 2391da398..1cea000f9 100644
--- a/src/lib/services/tasks.ts
+++ b/src/lib/services/tasks.ts
@@ -1,25 +1,25 @@
 import { Prisma } from '@prisma/client';
-import { default as db } from '$lib/server/database';
+import { default as db } from '#lib/server/database.js';
 
-import { getContestTaskPairs } from '$lib/services/contest_task_pairs';
+import { getContestTaskPairs } from '#lib/services/contest_task_pairs.js';
 
-import { ContestType } from '$lib/contests/types/contest';
-import type { Task, Tasks, TaskGrade } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import type { Task, Tasks, TaskGrade } from '#lib/types/task.js';
 import type {
   ContestTaskPair,
   ContestTaskPairKey,
   TaskMapByContestTaskPair,
-} from '$lib/types/contest_task_pair';
+} from '#lib/types/contest_task_pair.js';
 
 import {
   getCachedTasksMap,
   getCachedMergedTasksMap,
   invalidateTaskCaches,
-} from '$lib/server/tasks/cache';
+} from '#lib/server/tasks/cache.js';
 import { invalidateVoteCaches } from '$features/votes/server/cache';
 
-import { classifyContest } from '$lib/contests';
-import { createContestTaskPairKey } from '$lib/utils/contest_task_pair';
+import { classifyContest } from '#lib/contests/index.js';
+import { createContestTaskPairKey } from '#lib/utils/contest_task_pair.js';
 
 // See:
 // https://www.prisma.io/docs/concepts/components/prisma-client/filtering-and-sorting
diff --git a/src/lib/services/users.ts b/src/lib/services/users.ts
index c59badddc..5699f497d 100644
--- a/src/lib/services/users.ts
+++ b/src/lib/services/users.ts
@@ -1,4 +1,4 @@
-import { default as db } from '$lib/server/database';
+import { default as db } from '#lib/server/database.js';
 
 export async function getUser(username: string) {
   return await db.user.findUnique({
diff --git a/src/lib/stores/active_problem_list_tab.svelte.ts b/src/lib/stores/active_problem_list_tab.svelte.ts
index 07fded4a2..3ea21e4b5 100644
--- a/src/lib/stores/active_problem_list_tab.svelte.ts
+++ b/src/lib/stores/active_problem_list_tab.svelte.ts
@@ -1,4 +1,4 @@
-import { useLocalStorage } from '$lib/stores/local_storage_helper.svelte';
+import { useLocalStorage } from '#lib/stores/local_storage_helper.svelte.js';
 
 export type ActiveProblemListTab = 'contestTable' | 'listByGrade' | 'gradeGuidelineTable';
 
diff --git a/src/lib/types/authorship.ts b/src/lib/types/authorship.ts
index 1d50a4c57..9f712745d 100644
--- a/src/lib/types/authorship.ts
+++ b/src/lib/types/authorship.ts
@@ -1,4 +1,4 @@
-import type { Roles } from '$lib/types/user';
+import type { Roles } from '#lib/types/user.js';
 
 export type Authorship = {
   authorId: string;
diff --git a/src/lib/types/contest_task_pair.ts b/src/lib/types/contest_task_pair.ts
index d22866471..1469848c9 100644
--- a/src/lib/types/contest_task_pair.ts
+++ b/src/lib/types/contest_task_pair.ts
@@ -1,6 +1,6 @@
 import type { ContestTaskPair as ContestTaskPairOrigin } from '@prisma/client';
 
-import type { Task, TaskResult } from '$lib/types/task';
+import type { Task, TaskResult } from '#lib/types/task.js';
 
 export type ContestTaskPair = ContestTaskPairOrigin;
 
diff --git a/src/lib/types/task.ts b/src/lib/types/task.ts
index 2ab3dbef9..a53e8f28e 100644
--- a/src/lib/types/task.ts
+++ b/src/lib/types/task.ts
@@ -1,6 +1,6 @@
 // Import original enum as type.
 import type { TaskGrade as TaskGradeOrigin } from '@prisma/client';
-import type { ContestType } from '$lib/contests/types/contest';
+import type { ContestType } from '#lib/contests/types/contest.js';
 
 export interface Task {
   contest_type?: ContestType;
diff --git a/src/lib/utils/account_transfer.ts b/src/lib/utils/account_transfer.ts
index c3578176f..cc066818d 100644
--- a/src/lib/utils/account_transfer.ts
+++ b/src/lib/utils/account_transfer.ts
@@ -1,11 +1,11 @@
 import type { User } from '@prisma/client';
 
-import type { Roles } from '$lib/types/user';
-import type { TaskResult } from '$lib/types/task';
-import type { FloatingMessages } from '$lib/types/floating_message';
+import type { Roles } from '#lib/types/user.js';
+import type { TaskResult } from '#lib/types/task.js';
+import type { FloatingMessages } from '#lib/types/floating_message.js';
 
-import { sanitizeHTML } from '$lib/utils/html';
-import { isAdmin } from '$lib/utils/authorship';
+import { sanitizeHTML } from '#lib/utils/html.js';
+import { isAdmin } from '#lib/utils/authorship.js';
 
 export function isSameUser(source: User, destination: User): boolean {
   return source.username.toLocaleLowerCase() === destination.username.toLocaleLowerCase();
diff --git a/src/lib/utils/auth_forms.ts b/src/lib/utils/auth_forms.ts
index 186b86f6e..7de8afb26 100644
--- a/src/lib/utils/auth_forms.ts
+++ b/src/lib/utils/auth_forms.ts
@@ -7,11 +7,11 @@ import type {
   AuthForm,
   AuthFormCreationStrategies,
   AuthFormValidationStrategies,
-} from '$lib/types/auth_forms';
+} from '#lib/types/auth_forms.js';
 
-import { authSchema } from '$lib/zod/schema';
-import { SEE_OTHER } from '$lib/constants/http-response-status-codes';
-import { HOME_PAGE } from '$lib/constants/navbar-links';
+import { authSchema } from '#lib/zod/schema.js';
+import { SEE_OTHER } from '#lib/constants/http-response-status-codes.js';
+import { HOME_PAGE } from '#lib/constants/navbar-links.js';
 
 /**
  * Initialize authentication form pages (login/signup)
diff --git a/src/lib/utils/authorship.test.ts b/src/lib/utils/authorship.test.ts
index 0de3c4c5c..f86ffaeca 100644
--- a/src/lib/utils/authorship.test.ts
+++ b/src/lib/utils/authorship.test.ts
@@ -1,15 +1,15 @@
 import { expect, test, describe } from 'vitest';
 
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 
 import type {
   Authorship,
   AuthorshipForRead,
   AuthorshipForEdit,
   AuthorshipForDelete,
-} from '$lib/types/authorship';
+} from '#lib/types/authorship.js';
 
-import { isAdmin, hasAuthority, canRead, canEdit, canDelete } from '$lib/utils/authorship';
+import { isAdmin, hasAuthority, canRead, canEdit, canDelete } from '#lib/utils/authorship.js';
 
 const adminId = '1';
 const userId1 = '2';
diff --git a/src/lib/utils/authorship.ts b/src/lib/utils/authorship.ts
index e489a6fe5..223fcbe3b 100644
--- a/src/lib/utils/authorship.ts
+++ b/src/lib/utils/authorship.ts
@@ -1,4 +1,4 @@
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 
 /**
  * Validate if the user has admin role
diff --git a/src/lib/utils/contest_task_pair.ts b/src/lib/utils/contest_task_pair.ts
index b068352a5..93b8b4f85 100644
--- a/src/lib/utils/contest_task_pair.ts
+++ b/src/lib/utils/contest_task_pair.ts
@@ -1,4 +1,4 @@
-import type { ContestTaskPairKey } from '$lib/types/contest_task_pair';
+import type { ContestTaskPairKey } from '#lib/types/contest_task_pair.js';
 
 /**
  * Creates a unique key for a ContestTaskPair using contestId and taskId.
diff --git a/src/lib/utils/task.ts b/src/lib/utils/task.ts
index ae57371ab..5d768b311 100644
--- a/src/lib/utils/task.ts
+++ b/src/lib/utils/task.ts
@@ -1,16 +1,16 @@
-import { ContestType } from '$lib/contests/types/contest';
-import { type TaskResult, type TaskResults, TaskGrade, type TaskGrades } from '$lib/types/task';
-import type { UrlGenerator, UrlGenerators } from '$lib/types/url';
+import { ContestType } from '#lib/contests/types/contest.js';
+import { type TaskResult, type TaskResults, TaskGrade, type TaskGrades } from '#lib/types/task.js';
+import type { UrlGenerator, UrlGenerators } from '#lib/types/url.js';
 
 import { type WorkBookTaskBase } from '$features/workbooks/types/workbook';
 
-import { ATCODER_BASE_CONTEST_URL, AOJ_TASKS_URL } from '$lib/constants/urls';
+import { ATCODER_BASE_CONTEST_URL, AOJ_TASKS_URL } from '#lib/constants/urls.js';
 import {
   getPrefixForAojCourses,
   getContestPriority,
   regexForAojUniversity,
   regexForJag,
-} from '$lib/contests';
+} from '#lib/contests/index.js';
 
 // TODO: Codeforces、yukicoder、BOJなどに対応できるようにする
 /**
diff --git a/src/lib/utils/task_filter.ts b/src/lib/utils/task_filter.ts
index 20ad9f281..54fe9561c 100644
--- a/src/lib/utils/task_filter.ts
+++ b/src/lib/utils/task_filter.ts
@@ -1,5 +1,5 @@
-import { getContestNameLabel } from '$lib/contests';
-import { getTaskUrl } from '$lib/utils/task';
+import { getContestNameLabel } from '#lib/contests/index.js';
+import { getTaskUrl } from '#lib/utils/task.js';
 
 type SearchableTask = {
   title: string;
diff --git a/src/lib/utils/task_grade.test.ts b/src/lib/utils/task_grade.test.ts
index 760bd4ec7..acc8d828e 100644
--- a/src/lib/utils/task_grade.test.ts
+++ b/src/lib/utils/task_grade.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
-import { taskGradeValues, TaskGrade } from '$lib/types/task';
-import { isValidTaskGrade } from '$lib/utils/task_grade';
+import { taskGradeValues, TaskGrade } from '#lib/types/task.js';
+import { isValidTaskGrade } from '#lib/utils/task_grade.js';
 
 describe('isValidTaskGrade', () => {
   describe('successful cases', () => {
diff --git a/src/lib/utils/task_grade.ts b/src/lib/utils/task_grade.ts
index 89ffb5aed..d9bc7696f 100644
--- a/src/lib/utils/task_grade.ts
+++ b/src/lib/utils/task_grade.ts
@@ -1,4 +1,4 @@
-import { taskGradeValues, type TaskGrade } from '$lib/types/task';
+import { taskGradeValues, type TaskGrade } from '#lib/types/task.js';
 
 /**
  * Type guard to validate if an unknown value is a valid TaskGrade.
diff --git a/src/lib/utils/url.test.ts b/src/lib/utils/url.test.ts
index 7fa190b20..536d6ff9a 100644
--- a/src/lib/utils/url.test.ts
+++ b/src/lib/utils/url.test.ts
@@ -1,6 +1,6 @@
 import { expect, test, describe } from 'vitest';
 
-import { isValidUrl, isValidUrlSlug, sanitizeUrl, isSameOriginRedirect } from '$lib/utils/url';
+import { isValidUrl, isValidUrlSlug, sanitizeUrl, isSameOriginRedirect } from '#lib/utils/url.js';
 
 type TestCaseForUrlValidation = {
   rawUrl: string;
diff --git a/src/routes/(admin)/account_transfer/+page.server.ts b/src/routes/(admin)/account_transfer/+page.server.ts
index d07f204af..7836e0567 100644
--- a/src/routes/(admin)/account_transfer/+page.server.ts
+++ b/src/routes/(admin)/account_transfer/+page.server.ts
@@ -4,10 +4,10 @@ import { type Actions } from '@sveltejs/kit';
 import { superValidate } from 'sveltekit-superforms/server';
 import { zod4 } from 'sveltekit-superforms/adapters';
 
-import * as taskResultService from '$lib/services/task_results';
+import * as taskResultService from '#lib/services/task_results.js';
 
-import { accountTransferSchema } from '$lib/zod/schema';
-import type { FloatingMessage } from '$lib/types/floating_message';
+import { accountTransferSchema } from '#lib/zod/schema.js';
+import type { FloatingMessage } from '#lib/types/floating_message.js';
 
 import { validateAdminAccess } from '$features/auth/services/admin_access';
 
diff --git a/src/routes/(admin)/account_transfer/+page.svelte b/src/routes/(admin)/account_transfer/+page.svelte
index 06f06795e..ff52a06ca 100644
--- a/src/routes/(admin)/account_transfer/+page.svelte
+++ b/src/routes/(admin)/account_transfer/+page.svelte
@@ -15,11 +15,11 @@
   import BadgeCheck from '@lucide/svelte/icons/badge-check';
   import Ban from '@lucide/svelte/icons/ban';
 
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
-  import ContainerWrapper from '$lib/components/ContainerWrapper.svelte';
-  import MessageHelperWrapper from '$lib/components/MessageHelperWrapper.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
+  import ContainerWrapper from '#lib/components/ContainerWrapper.svelte';
+  import MessageHelperWrapper from '#lib/components/MessageHelperWrapper.svelte';
 
-  import type { FloatingMessages } from '$lib/types/floating_message';
+  import type { FloatingMessages } from '#lib/types/floating_message.js';
 
   interface Props {
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
diff --git a/src/routes/(admin)/tags/+page.server.ts b/src/routes/(admin)/tags/+page.server.ts
index b720872ce..e7b31c257 100644
--- a/src/routes/(admin)/tags/+page.server.ts
+++ b/src/routes/(admin)/tags/+page.server.ts
@@ -1,8 +1,8 @@
 import { redirect, type Actions } from '@sveltejs/kit';
 
-import type { Tag } from '$lib/types/tag';
+import type { Tag } from '#lib/types/tag.js';
 
-import * as tagService from '$lib/services/tags';
+import * as tagService from '#lib/services/tags.js';
 
 import { validateAdminAccess } from '$features/auth/services/admin_access';
 
diff --git a/src/routes/(admin)/tags/+page.svelte b/src/routes/(admin)/tags/+page.svelte
index 3bfa1ec62..e22807c60 100644
--- a/src/routes/(admin)/tags/+page.svelte
+++ b/src/routes/(admin)/tags/+page.svelte
@@ -1,6 +1,6 @@
 <script lang="ts">
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
-  import TagListForEdit from '$lib/components/TagListForEdit.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
+  import TagListForEdit from '#lib/components/TagListForEdit.svelte';
 
   let { data } = $props();
   let tags = data.tags;
diff --git a/src/routes/(admin)/tags/[tag_id]/+page.server.ts b/src/routes/(admin)/tags/[tag_id]/+page.server.ts
index 8dab72662..249af0350 100644
--- a/src/routes/(admin)/tags/[tag_id]/+page.server.ts
+++ b/src/routes/(admin)/tags/[tag_id]/+page.server.ts
@@ -1,12 +1,12 @@
 import { error } from '@sveltejs/kit';
 
-import type { Tasks } from '$lib/types/task';
+import type { Tasks } from '#lib/types/task.js';
 
 import { validateAdminAccess } from '$features/auth/services/admin_access';
-import * as tagService from '$lib/services/tags';
-import * as taskTagService from '$lib/services/task_tags';
+import * as tagService from '#lib/services/tags.js';
+import * as taskTagService from '#lib/services/task_tags.js';
 
-import { NOT_FOUND } from '$lib/constants/http-response-status-codes';
+import { NOT_FOUND } from '#lib/constants/http-response-status-codes.js';
 
 export async function load({ locals, params, url }) {
   await validateAdminAccess(locals, url);
diff --git a/src/routes/(admin)/tags/[tag_id]/+page.svelte b/src/routes/(admin)/tags/[tag_id]/+page.svelte
index c4d3dc791..ddf77522c 100644
--- a/src/routes/(admin)/tags/[tag_id]/+page.svelte
+++ b/src/routes/(admin)/tags/[tag_id]/+page.svelte
@@ -1,5 +1,5 @@
 <script lang="ts">
-  import TagForm from '$lib/components/TagForm.svelte';
+  import TagForm from '#lib/components/TagForm.svelte';
 
   let { data } = $props();
 
diff --git a/src/routes/(admin)/tasks/+page.server.ts b/src/routes/(admin)/tasks/+page.server.ts
index 2975674c2..b56ceea42 100644
--- a/src/routes/(admin)/tasks/+page.server.ts
+++ b/src/routes/(admin)/tasks/+page.server.ts
@@ -1,17 +1,17 @@
 import { fail, type Actions } from '@sveltejs/kit';
 
-import type { Contests, ContestForImport, ContestsForImport } from '$lib/contests/types/contest';
-import { type Task, type Tasks, type TaskForImport, type TasksForImport } from '$lib/types/task';
+import type { Contests, ContestForImport, ContestsForImport } from '#lib/contests/types/contest.js';
+import { type Task, type Tasks, type TaskForImport, type TasksForImport } from '#lib/types/task.js';
 
-import * as taskService from '$lib/services/tasks';
+import * as taskService from '#lib/services/tasks.js';
 import { validateAdminAccess } from '$features/auth/services/admin_access';
 
-import { fetchContests, fetchTasks, isContestTaskImportSource } from '$lib/clients';
+import { fetchContests, fetchTasks, isContestTaskImportSource } from '#lib/clients/index.js';
 
-import { classifyContest } from '$lib/contests';
-import { sha256 } from '$lib/utils/hash';
+import { classifyContest } from '#lib/contests/index.js';
+import { sha256 } from '#lib/utils/hash.js';
 
-import { BAD_REQUEST, INTERNAL_SERVER_ERROR } from '$lib/constants/http-response-status-codes';
+import { BAD_REQUEST, INTERNAL_SERVER_ERROR } from '#lib/constants/http-response-status-codes.js';
 
 export async function load({ locals, url }) {
   await validateAdminAccess(locals, url);
diff --git a/src/routes/(admin)/tasks/+page.svelte b/src/routes/(admin)/tasks/+page.svelte
index 9df4e1ec4..b5f620711 100644
--- a/src/routes/(admin)/tasks/+page.svelte
+++ b/src/routes/(admin)/tasks/+page.svelte
@@ -5,12 +5,12 @@
 
   import { Select, Label, Button, PaginationNav } from 'flowbite-svelte';
 
-  import type { Contests } from '$lib/contests/types/contest';
+  import type { Contests } from '#lib/contests/types/contest.js';
 
-  import { importSourceEntries, type ContestTaskImportSource } from '$lib/clients';
+  import { importSourceEntries, type ContestTaskImportSource } from '#lib/clients/index.js';
 
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
-  import SpinnerWrapper from '$lib/components/SpinnerWrapper.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
+  import SpinnerWrapper from '#lib/components/SpinnerWrapper.svelte';
   import TaskTableForImport from './_components/TaskTableForImport.svelte';
   import TaskSearchBox from './_components/TaskSearchBox.svelte';
 
diff --git a/src/routes/(admin)/tasks/[task_id]/+page.server.ts b/src/routes/(admin)/tasks/[task_id]/+page.server.ts
index f231b4264..8d3f94b4d 100644
--- a/src/routes/(admin)/tasks/[task_id]/+page.server.ts
+++ b/src/routes/(admin)/tasks/[task_id]/+page.server.ts
@@ -1,16 +1,16 @@
 import { fail, type Actions } from '@sveltejs/kit';
 
-import { type Tasks, type TaskGrade, getTaskGrade } from '$lib/types/task';
-import type { Tag } from '$lib/types/tag';
-import type { ImportTaskTag } from '$lib/types/tasktag';
+import { type Tasks, type TaskGrade, getTaskGrade } from '#lib/types/task.js';
+import type { Tag } from '#lib/types/tag.js';
+import type { ImportTaskTag } from '#lib/types/tasktag.js';
 
-import * as taskService from '$lib/services/tasks';
-import * as taskTagsApiService from '$lib/services/tasktagsApiService';
-import * as taskTagsService from '$lib/services/task_tags';
+import * as taskService from '#lib/services/tasks.js';
+import * as taskTagsApiService from '#lib/services/tasktagsApiService.js';
+import * as taskTagsService from '#lib/services/task_tags.js';
 
 import { validateAdminAccess } from '$features/auth/services/admin_access';
 
-import { BAD_REQUEST, INTERNAL_SERVER_ERROR } from '$lib/constants/http-response-status-codes';
+import { BAD_REQUEST, INTERNAL_SERVER_ERROR } from '#lib/constants/http-response-status-codes.js';
 
 export async function load({ locals, params, url }) {
   await validateAdminAccess(locals, url);
diff --git a/src/routes/(admin)/tasks/[task_id]/+page.svelte b/src/routes/(admin)/tasks/[task_id]/+page.svelte
index e38c82478..fd269c19e 100644
--- a/src/routes/(admin)/tasks/[task_id]/+page.svelte
+++ b/src/routes/(admin)/tasks/[task_id]/+page.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
-  import TaskForm from '$lib/components/TaskForm.svelte';
-  import TagListForEdit from '$lib/components/TagListForEdit.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
+  import TaskForm from '#lib/components/TaskForm.svelte';
+  import TagListForEdit from '#lib/components/TagListForEdit.svelte';
 
   let { data } = $props();
 
diff --git a/src/routes/(admin)/tasks/_components/TaskTableForImport.svelte b/src/routes/(admin)/tasks/_components/TaskTableForImport.svelte
index f556a4985..3ef0c9d6d 100644
--- a/src/routes/(admin)/tasks/_components/TaskTableForImport.svelte
+++ b/src/routes/(admin)/tasks/_components/TaskTableForImport.svelte
@@ -13,10 +13,10 @@
     Label,
   } from 'flowbite-svelte';
 
-  import type { Contests } from '$lib/contests/types/contest';
-  import type { ContestTaskImportSource } from '$lib/clients';
-  import { getContestNameLabel } from '$lib/contests';
-  import { newline } from '$lib/utils/newline';
+  import type { Contests } from '#lib/contests/types/contest.js';
+  import type { ContestTaskImportSource } from '#lib/clients/index.js';
+  import { getContestNameLabel } from '#lib/contests/index.js';
+  import { newline } from '#lib/utils/newline.js';
 
   interface Props {
     importContests: Contests;
diff --git a/src/routes/(admin)/tasks/_utils/contests.test.ts b/src/routes/(admin)/tasks/_utils/contests.test.ts
index aab04a36a..db274ae1e 100644
--- a/src/routes/(admin)/tasks/_utils/contests.test.ts
+++ b/src/routes/(admin)/tasks/_utils/contests.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 import { filterContests } from './contests';
-import type { Contests } from '$lib/contests/types/contest';
+import type { Contests } from '#lib/contests/types/contest.js';
 
 const contests: Contests = [
   {
diff --git a/src/routes/(admin)/tasks/_utils/contests.ts b/src/routes/(admin)/tasks/_utils/contests.ts
index a02ed0f29..128d0e8a7 100644
--- a/src/routes/(admin)/tasks/_utils/contests.ts
+++ b/src/routes/(admin)/tasks/_utils/contests.ts
@@ -1,4 +1,4 @@
-import type { Contests } from '$lib/contests/types/contest';
+import type { Contests } from '#lib/contests/types/contest.js';
 
 export function filterContests(contests: Contests, query: string): Contests {
   const hasNoQuery = !query || query.trim() === '';
diff --git a/src/routes/(admin)/tasks/grade/+page.server.ts b/src/routes/(admin)/tasks/grade/+page.server.ts
index 68da7c6e8..e550326d9 100644
--- a/src/routes/(admin)/tasks/grade/+page.server.ts
+++ b/src/routes/(admin)/tasks/grade/+page.server.ts
@@ -1,8 +1,8 @@
 import type { Actions, PageServerLoad } from './$types';
 
-import { type TaskGrade, TaskGrade as TaskGradeEnum } from '$lib/types/task';
+import { type TaskGrade, TaskGrade as TaskGradeEnum } from '#lib/types/task.js';
 
-import { updateTask } from '$lib/services/tasks';
+import { updateTask } from '#lib/services/tasks.js';
 import { getAllTasksWithVoteInfo } from '$features/votes/services/vote_statistics';
 import { validateAdminAccess } from '$features/auth/services/admin_access';
 
diff --git a/src/routes/(admin)/tasks/grade/+page.svelte b/src/routes/(admin)/tasks/grade/+page.svelte
index 16d18bfc3..464fc2956 100644
--- a/src/routes/(admin)/tasks/grade/+page.svelte
+++ b/src/routes/(admin)/tasks/grade/+page.svelte
@@ -1,5 +1,5 @@
 <script lang="ts">
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
   import TaskGradeTable from './_components/TaskGradeTable.svelte';
 
   let { data } = $props();
diff --git a/src/routes/(admin)/tasks/grade/_components/TaskGradeTable.svelte b/src/routes/(admin)/tasks/grade/_components/TaskGradeTable.svelte
index 730c96dd2..75197c6da 100644
--- a/src/routes/(admin)/tasks/grade/_components/TaskGradeTable.svelte
+++ b/src/routes/(admin)/tasks/grade/_components/TaskGradeTable.svelte
@@ -13,18 +13,18 @@
     PaginationNav,
   } from 'flowbite-svelte';
 
-  import GradeLabel from '$lib/components/GradeLabel.svelte';
+  import GradeLabel from '#lib/components/GradeLabel.svelte';
   import RelativeEvaluationBadge from '$features/votes/components/RelativeEvaluationBadge.svelte';
 
-  import { taskGradeValues, TaskGrade } from '$lib/types/task';
+  import { taskGradeValues, TaskGrade } from '#lib/types/task.js';
   import type { TaskWithVoteInfo } from '$features/votes/services/vote_statistics';
 
-  import { addContestNameToTaskIndex } from '$lib/contests';
+  import { addContestNameToTaskIndex } from '#lib/contests/index.js';
   import {
     getTaskGradeLabel,
     compareByContestIdAndTaskId,
     removeTaskIndexFromTitle,
-  } from '$lib/utils/task';
+  } from '#lib/utils/task.js';
 
   import { filterGradeTableTasks, countPendingTasks } from '../_utils/grade_table_filter';
 
diff --git a/src/routes/(admin)/tasks/grade/_utils/grade_table_filter.test.ts b/src/routes/(admin)/tasks/grade/_utils/grade_table_filter.test.ts
index 191903a90..0ac592928 100644
--- a/src/routes/(admin)/tasks/grade/_utils/grade_table_filter.test.ts
+++ b/src/routes/(admin)/tasks/grade/_utils/grade_table_filter.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import type { TaskWithVoteInfo } from '$features/votes/services/vote_statistics';
 
 import { countPendingTasks, filterGradeTableTasks } from './grade_table_filter';
diff --git a/src/routes/(admin)/tasks/grade/_utils/grade_table_filter.ts b/src/routes/(admin)/tasks/grade/_utils/grade_table_filter.ts
index cf8e9c6b4..a11e87af4 100644
--- a/src/routes/(admin)/tasks/grade/_utils/grade_table_filter.ts
+++ b/src/routes/(admin)/tasks/grade/_utils/grade_table_filter.ts
@@ -1,6 +1,6 @@
 import type { TaskWithVoteInfo } from '$features/votes/services/vote_statistics';
-import { TaskGrade } from '$lib/types/task';
-import { filterTasksBySearch } from '$lib/utils/task_filter';
+import { TaskGrade } from '#lib/types/task.js';
+import { filterTasksBySearch } from '#lib/utils/task_filter.js';
 
 /**
  * Applies the grade-table search rule.
diff --git a/src/routes/(admin)/workbooks/order/+page.svelte b/src/routes/(admin)/workbooks/order/+page.svelte
index c0f255669..e1e9e6ba2 100644
--- a/src/routes/(admin)/workbooks/order/+page.svelte
+++ b/src/routes/(admin)/workbooks/order/+page.svelte
@@ -1,8 +1,8 @@
 <script lang="ts">
   import type { PageData } from './$types';
 
-  import ContainerWrapper from '$lib/components/ContainerWrapper.svelte';
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
+  import ContainerWrapper from '#lib/components/ContainerWrapper.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
   import KanbanBoard from './_components/KanbanBoard.svelte';
 
   let { data }: { data: PageData } = $props();
diff --git a/src/routes/(admin)/workbooks/order/+server.ts b/src/routes/(admin)/workbooks/order/+server.ts
index 14f23e328..81aeb6415 100644
--- a/src/routes/(admin)/workbooks/order/+server.ts
+++ b/src/routes/(admin)/workbooks/order/+server.ts
@@ -6,7 +6,7 @@ import { updatePlacementsSchema } from '$features/workbooks/zod/schema';
 
 import { validateAdminAccessForApi } from '$features/auth/services/admin_access';
 
-import { BAD_REQUEST } from '$lib/constants/http-response-status-codes';
+import { BAD_REQUEST } from '#lib/constants/http-response-status-codes.js';
 
 export async function POST({ request, locals }: RequestEvent) {
   await validateAdminAccessForApi(locals);
diff --git a/src/routes/(admin)/workbooks/order/_components/KanbanBoard.svelte b/src/routes/(admin)/workbooks/order/_components/KanbanBoard.svelte
index c39bb9616..619c93b9b 100644
--- a/src/routes/(admin)/workbooks/order/_components/KanbanBoard.svelte
+++ b/src/routes/(admin)/workbooks/order/_components/KanbanBoard.svelte
@@ -14,7 +14,7 @@
     SolutionCategory,
     type WorkbooksWithPlacement,
   } from '$features/workbooks/types/workbook_placement';
-  import { TaskGrade } from '$lib/types/task';
+  import { TaskGrade } from '#lib/types/task.js';
   import type {
     KanbanColumns,
     DragOverEventArg,
diff --git a/src/routes/(admin)/workbooks/order/_components/KanbanTabBar.svelte b/src/routes/(admin)/workbooks/order/_components/KanbanTabBar.svelte
index 3e8714ee6..879426fb4 100644
--- a/src/routes/(admin)/workbooks/order/_components/KanbanTabBar.svelte
+++ b/src/routes/(admin)/workbooks/order/_components/KanbanTabBar.svelte
@@ -3,14 +3,14 @@
 
   import { Tabs } from 'flowbite-svelte';
 
-  import { TaskGrade } from '$lib/types/task';
+  import { TaskGrade } from '#lib/types/task.js';
   import { SolutionCategory, SOLUTION_LABELS } from '$features/workbooks/types/workbook_placement';
   import type { ActiveTab } from '../_types/kanban';
 
-  import TabItemWrapper from '$lib/components/Tabs/TabItemWrapper.svelte';
+  import TabItemWrapper from '#lib/components/Tabs/TabItemWrapper.svelte';
   import ColumnSelector from './ColumnSelector.svelte';
 
-  import { getTaskGradeLabel } from '$lib/utils/task';
+  import { getTaskGradeLabel } from '#lib/utils/task.js';
 
   const SOLUTION_CATEGORY_OPTIONS = Object.entries(SolutionCategory)
     .filter(([category]) => category !== SolutionCategory.PENDING)
diff --git a/src/routes/(admin)/workbooks/order/_fixtures/kanban.ts b/src/routes/(admin)/workbooks/order/_fixtures/kanban.ts
index e2785b4dc..8ea47b18d 100644
--- a/src/routes/(admin)/workbooks/order/_fixtures/kanban.ts
+++ b/src/routes/(admin)/workbooks/order/_fixtures/kanban.ts
@@ -1,4 +1,4 @@
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import { WorkBookType } from '$features/workbooks/types/workbook';
 import {
   SolutionCategory,
diff --git a/src/routes/(admin)/workbooks/order/_utils/kanban.test.ts b/src/routes/(admin)/workbooks/order/_utils/kanban.test.ts
index f91d03e23..4321bf731 100644
--- a/src/routes/(admin)/workbooks/order/_utils/kanban.test.ts
+++ b/src/routes/(admin)/workbooks/order/_utils/kanban.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect } from 'vitest';
 
 import { SolutionCategory } from '$features/workbooks/types/workbook_placement';
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 
 import { workbooks, solutionColumnsBefore, solutionColumnsGraphSwapped } from '../_fixtures/kanban';
 import {
diff --git a/src/routes/(admin)/workbooks/order/_utils/kanban.ts b/src/routes/(admin)/workbooks/order/_utils/kanban.ts
index 0567362b2..4d3a11be9 100644
--- a/src/routes/(admin)/workbooks/order/_utils/kanban.ts
+++ b/src/routes/(admin)/workbooks/order/_utils/kanban.ts
@@ -1,4 +1,4 @@
-import { TaskGrade } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
 import {
   SolutionCategory,
   SOLUTION_LABELS,
@@ -14,7 +14,7 @@ import type {
   TabConfig,
 } from '../_types/kanban';
 
-import { getTaskGradeLabel } from '$lib/utils/task';
+import { getTaskGradeLabel } from '#lib/utils/task.js';
 
 // Per-tab static configuration; eliminates activeTab === 'solution' branches in DnD handlers
 export const TAB_CONFIGS: Record<ActiveTab, TabConfig> = {
diff --git a/src/routes/(auth)/login/+page.server.ts b/src/routes/(auth)/login/+page.server.ts
index 2aa11dec6..05880d92b 100644
--- a/src/routes/(auth)/login/+page.server.ts
+++ b/src/routes/(auth)/login/+page.server.ts
@@ -5,15 +5,15 @@ import { fail, redirect } from '@sveltejs/kit';
 import { createSession } from '$features/auth/server/session';
 import { authenticateUser } from '$features/auth/services/credentials';
 
-import { initializeAuthForm, validateAuthFormWithFallback } from '$lib/utils/auth_forms';
-import { isSameOriginRedirect } from '$lib/utils/url';
+import { initializeAuthForm, validateAuthFormWithFallback } from '#lib/utils/auth_forms.js';
+import { isSameOriginRedirect } from '#lib/utils/url.js';
 
 import {
   BAD_REQUEST,
   SEE_OTHER,
   INTERNAL_SERVER_ERROR,
-} from '$lib/constants/http-response-status-codes';
-import { HOME_PAGE } from '$lib/constants/navbar-links';
+} from '#lib/constants/http-response-status-codes.js';
+import { HOME_PAGE } from '#lib/constants/navbar-links.js';
 
 import type { Actions, PageServerLoad } from './$types';
 
diff --git a/src/routes/(auth)/login/+page.svelte b/src/routes/(auth)/login/+page.svelte
index 77e6c7593..7ce85a1f2 100644
--- a/src/routes/(auth)/login/+page.svelte
+++ b/src/routes/(auth)/login/+page.svelte
@@ -3,11 +3,11 @@
   import { page } from '$app/state';
   import { superForm } from 'sveltekit-superforms/client';
 
-  import AuthForm from '$lib/components/AuthForm.svelte';
+  import AuthForm from '#lib/components/AuthForm.svelte';
 
   import { buildSignupPath } from '$features/auth/utils/signup';
 
-  import { CREATE_ACCOUNT_LABEL, LOGIN_LABEL } from '$lib/constants/forms';
+  import { CREATE_ACCOUNT_LABEL, LOGIN_LABEL } from '#lib/constants/forms.js';
 
   interface Props {
     data: PageData;
diff --git a/src/routes/(auth)/logout/+page.server.ts b/src/routes/(auth)/logout/+page.server.ts
index f7802255f..f3514e8a9 100644
--- a/src/routes/(auth)/logout/+page.server.ts
+++ b/src/routes/(auth)/logout/+page.server.ts
@@ -2,8 +2,8 @@ import { fail, redirect } from '@sveltejs/kit';
 
 import { invalidateSession } from '$features/auth/server/session';
 
-import { SEE_OTHER, UNAUTHORIZED } from '$lib/constants/http-response-status-codes';
-import { HOME_PAGE } from '$lib/constants/navbar-links';
+import { SEE_OTHER, UNAUTHORIZED } from '#lib/constants/http-response-status-codes.js';
+import { HOME_PAGE } from '#lib/constants/navbar-links.js';
 
 import type { Actions } from './$types';
 
diff --git a/src/routes/(auth)/signup/+page.server.ts b/src/routes/(auth)/signup/+page.server.ts
index 95db3feea..858991f67 100644
--- a/src/routes/(auth)/signup/+page.server.ts
+++ b/src/routes/(auth)/signup/+page.server.ts
@@ -5,15 +5,15 @@ import { fail, redirect } from '@sveltejs/kit';
 import { createSession } from '$features/auth/server/session';
 import { registerUser } from '$features/auth/services/credentials';
 
-import { initializeAuthForm, validateAuthFormWithFallback } from '$lib/utils/auth_forms';
-import { isSameOriginRedirect } from '$lib/utils/url';
+import { initializeAuthForm, validateAuthFormWithFallback } from '#lib/utils/auth_forms.js';
+import { isSameOriginRedirect } from '#lib/utils/url.js';
 
 import {
   SEE_OTHER,
   BAD_REQUEST,
   INTERNAL_SERVER_ERROR,
-} from '$lib/constants/http-response-status-codes';
-import { HOME_PAGE } from '$lib/constants/navbar-links';
+} from '#lib/constants/http-response-status-codes.js';
+import { HOME_PAGE } from '#lib/constants/navbar-links.js';
 
 import type { Actions, PageServerLoad } from './$types';
 
diff --git a/src/routes/(auth)/signup/+page.svelte b/src/routes/(auth)/signup/+page.svelte
index ee5834c1a..3ab3770bb 100644
--- a/src/routes/(auth)/signup/+page.svelte
+++ b/src/routes/(auth)/signup/+page.svelte
@@ -2,8 +2,8 @@
   import type { PageData } from './$types';
   import { superForm } from 'sveltekit-superforms/client';
 
-  import AuthForm from '$lib/components/AuthForm.svelte';
-  import { CREATE_ACCOUNT_LABEL, LOGIN_LABEL } from '$lib/constants/forms';
+  import AuthForm from '#lib/components/AuthForm.svelte';
+  import { CREATE_ACCOUNT_LABEL, LOGIN_LABEL } from '#lib/constants/forms.js';
 
   interface Props {
     data: PageData;
diff --git a/src/routes/+error.svelte b/src/routes/+error.svelte
index 048207563..9d95d3040 100644
--- a/src/routes/+error.svelte
+++ b/src/routes/+error.svelte
@@ -2,9 +2,9 @@
   import { page } from '$app/state';
 
   import { Heading, Button } from 'flowbite-svelte';
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
 
-  import { HOME_PAGE } from '$lib/constants/navbar-links';
+  import { HOME_PAGE } from '#lib/constants/navbar-links.js';
 </script>
 
 <div
diff --git a/src/routes/+layout.server.ts b/src/routes/+layout.server.ts
index 712255d78..081cde8d2 100644
--- a/src/routes/+layout.server.ts
+++ b/src/routes/+layout.server.ts
@@ -2,9 +2,9 @@ import {
   PRODUCT_DESCRIPTION,
   PRODUCT_NAME,
   TWITTER_HANDLE_NAME,
-} from '$lib/constants/product-info';
+} from '#lib/constants/product-info.js';
 
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 
 const getBaseMetaTags = (url: URL) => {
   const title: string = PRODUCT_NAME;
diff --git a/src/routes/+layout.svelte b/src/routes/+layout.svelte
index ea664ede6..f44d1d9c4 100644
--- a/src/routes/+layout.svelte
+++ b/src/routes/+layout.svelte
@@ -8,13 +8,13 @@
 
   import '../app.css';
 
-  import Header from '$lib/components/Header.svelte';
-  import GoogleAnalytics from '$lib/components/GoogleAnalytics.svelte';
-  import ErrorMessageToast from '$lib/components/ToastWrapper/ErrorMessageToast.svelte';
-  import SpinnerWrapper from '$lib/components/SpinnerWrapper.svelte';
-  import Footer from '$lib/components/Footer.svelte';
+  import Header from '#lib/components/Header.svelte';
+  import GoogleAnalytics from '#lib/components/GoogleAnalytics.svelte';
+  import ErrorMessageToast from '#lib/components/ToastWrapper/ErrorMessageToast.svelte';
+  import SpinnerWrapper from '#lib/components/SpinnerWrapper.svelte';
+  import Footer from '#lib/components/Footer.svelte';
 
-  import { errorMessageStore } from '$lib/stores/error_message';
+  import { errorMessageStore } from '#lib/stores/error_message.js';
 
   let { data, children } = $props();
 
diff --git a/src/routes/+page.server.ts b/src/routes/+page.server.ts
index 670e22ab4..1d864a9fd 100644
--- a/src/routes/+page.server.ts
+++ b/src/routes/+page.server.ts
@@ -1,5 +1,5 @@
 import type { PageServerLoad } from './$types';
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 
 export const load: PageServerLoad = async ({ locals }) => {
   const session = await locals.auth.validate();
diff --git a/src/routes/+page.svelte b/src/routes/+page.svelte
index db2b9a39f..7df60d46d 100644
--- a/src/routes/+page.svelte
+++ b/src/routes/+page.svelte
@@ -2,16 +2,16 @@
   import { Heading, Button, Carousel } from 'flowbite-svelte';
   import ArrowRight from '@lucide/svelte/icons/arrow-right';
 
-  import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
+  import ExternalLinkWrapper from '#lib/components/ExternalLinkWrapper.svelte';
 
-  import { PRODUCT_CATCH_PHRASE } from '$lib/constants/product-info';
-  import { ATCODER_BASE_URL, TASK_GRADE_CRITERIA_SHEET_URL } from '$lib/constants/urls';
+  import { PRODUCT_CATCH_PHRASE } from '#lib/constants/product-info.js';
+  import { ATCODER_BASE_URL, TASK_GRADE_CRITERIA_SHEET_URL } from '#lib/constants/urls.js';
   import {
     WORKBOOKS_PAGE,
     PROBLEMS_PAGE,
     VOTES_PAGE,
     ABOUT_PAGE,
-  } from '$lib/constants/navbar-links';
+  } from '#lib/constants/navbar-links.js';
 
   const problemImages = [
     {
diff --git a/src/routes/about/+page.svelte b/src/routes/about/+page.svelte
index f7c6d18ec..e07abc9d6 100644
--- a/src/routes/about/+page.svelte
+++ b/src/routes/about/+page.svelte
@@ -1,5 +1,5 @@
 <script lang="ts">
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
   import {
     sectionWithTitle,
     coreFeatures,
diff --git a/src/routes/about/SectionSnippets.svelte b/src/routes/about/SectionSnippets.svelte
index 0d7e2d4fc..5d18307e8 100644
--- a/src/routes/about/SectionSnippets.svelte
+++ b/src/routes/about/SectionSnippets.svelte
@@ -17,9 +17,9 @@
   import type { Snippet } from 'svelte';
   import { Heading, Li, List } from 'flowbite-svelte';
 
-  import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
+  import ExternalLinkWrapper from '#lib/components/ExternalLinkWrapper.svelte';
 
-  import { features, members } from '$lib/constants/product-info';
+  import { features, members } from '#lib/constants/product-info.js';
 </script>
 
 <!-- See: -->
diff --git a/src/routes/forgot_password/+page.server.ts b/src/routes/forgot_password/+page.server.ts
index b15da8d63..17c3bc662 100644
--- a/src/routes/forgot_password/+page.server.ts
+++ b/src/routes/forgot_password/+page.server.ts
@@ -1,6 +1,6 @@
 import { error } from '@sveltejs/kit';
 
-import { FORBIDDEN } from '$lib/constants/http-response-status-codes';
+import { FORBIDDEN } from '#lib/constants/http-response-status-codes.js';
 
 export async function load({ locals }) {
   const session = await locals.auth.validate();
diff --git a/src/routes/forgot_password/+page.svelte b/src/routes/forgot_password/+page.svelte
index e054ef5bb..e4f127b2b 100644
--- a/src/routes/forgot_password/+page.svelte
+++ b/src/routes/forgot_password/+page.svelte
@@ -1,13 +1,13 @@
 <script lang="ts">
   import { Heading, Card, Alert, Button, List, Li } from 'flowbite-svelte';
 
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
 
-  import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
+  import ExternalLinkWrapper from '#lib/components/ExternalLinkWrapper.svelte';
 
-  import { X_OFFICIAL_ACCOUNT_URL } from '$lib/constants/product-info';
-  import { LOGIN_PAGE } from '$lib/constants/navbar-links';
-  import { LOGIN_LABEL } from '$lib/constants/forms';
+  import { X_OFFICIAL_ACCOUNT_URL } from '#lib/constants/product-info.js';
+  import { LOGIN_PAGE } from '#lib/constants/navbar-links.js';
+  import { LOGIN_LABEL } from '#lib/constants/forms.js';
 </script>
 
 <!-- See: -->
diff --git a/src/routes/problems/+page.server.ts b/src/routes/problems/+page.server.ts
index 1551d2b35..676487dc0 100644
--- a/src/routes/problems/+page.server.ts
+++ b/src/routes/problems/+page.server.ts
@@ -2,13 +2,13 @@ import { fail, type Actions } from '@sveltejs/kit';
 import { superValidate } from 'sveltekit-superforms';
 import { zod4 } from 'sveltekit-superforms/adapters';
 
-import * as task_crud from '$lib/services/task_results';
+import * as task_crud from '#lib/services/task_results.js';
 import { getVoteGradeStatistics } from '$features/votes/services/vote_statistics';
-import type { TaskResults } from '$lib/types/task';
-import { updateTaskResult } from '$lib/actions/update_task_result';
+import type { TaskResults } from '#lib/types/task.js';
+import { updateTaskResult } from '#lib/actions/update_task_result.js';
 import { voteAbsoluteGrade } from '@/features/votes/actions/vote_actions';
 import { voteAbsoluteGradeSchema } from '$features/votes/zod/schema';
-import { BAD_REQUEST } from '$lib/constants/http-response-status-codes';
+import { BAD_REQUEST } from '#lib/constants/http-response-status-codes.js';
 
 // 一覧表ページは、ログインしていなくても閲覧できるようにする
 export async function load({ locals, url }) {
diff --git a/src/routes/problems/+page.svelte b/src/routes/problems/+page.svelte
index ca943f540..4b47b96b6 100644
--- a/src/routes/problems/+page.svelte
+++ b/src/routes/problems/+page.svelte
@@ -1,20 +1,20 @@
 <script lang="ts">
   import { Tabs } from 'flowbite-svelte';
 
-  import type { TaskResults } from '$lib/types/task';
+  import type { TaskResults } from '#lib/types/task.js';
 
-  import { compareByContestIdAndTaskId } from '$lib/utils/task';
+  import { compareByContestIdAndTaskId } from '#lib/utils/task.js';
 
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
-  import ProblemListTabItem from '$lib/components/Tabs/ProblemListTabItem.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
+  import ProblemListTabItem from '#lib/components/Tabs/ProblemListTabItem.svelte';
   import TaskTable from '$features/tasks/components/contest-table/TaskTable.svelte';
-  import TaskGradeList from '$lib/components/TaskGradeList.svelte';
-  import GradeGuidelineTable from '$lib/components/TaskGrades/GradeGuidelineTable.svelte';
+  import TaskGradeList from '#lib/components/TaskGradeList.svelte';
+  import GradeGuidelineTable from '#lib/components/TaskGrades/GradeGuidelineTable.svelte';
 
   import {
     activeProblemListTabStore,
     type ActiveProblemListTab,
-  } from '$lib/stores/active_problem_list_tab.svelte';
+  } from '#lib/stores/active_problem_list_tab.svelte.js';
 
   let { data } = $props();
 
diff --git a/src/routes/problems/[slug]/+page.server.ts b/src/routes/problems/[slug]/+page.server.ts
index a529830ba..03324c179 100644
--- a/src/routes/problems/[slug]/+page.server.ts
+++ b/src/routes/problems/[slug]/+page.server.ts
@@ -1,10 +1,10 @@
 import { fail, type Actions, redirect } from '@sveltejs/kit';
 
-import * as crud from '$lib/services/task_results';
-import { getButtons } from '$lib/services/submission_status';
+import * as crud from '#lib/services/task_results.js';
+import { getButtons } from '#lib/services/submission_status.js';
 import { getLoggedInUser } from '$features/auth/services/session_guards';
 
-import { BAD_REQUEST, TEMPORARY_REDIRECT } from '$lib/constants/http-response-status-codes';
+import { BAD_REQUEST, TEMPORARY_REDIRECT } from '#lib/constants/http-response-status-codes.js';
 
 const buttons = await getButtons();
 
diff --git a/src/routes/problems/[slug]/+page.svelte b/src/routes/problems/[slug]/+page.svelte
index b097ea511..7e6cc0578 100644
--- a/src/routes/problems/[slug]/+page.svelte
+++ b/src/routes/problems/[slug]/+page.svelte
@@ -4,11 +4,11 @@
   import { Breadcrumb, BreadcrumbItem, Img } from 'flowbite-svelte';
   import ExternalLink from '@lucide/svelte/icons/external-link';
 
-  import SubmissionStatusButton from '$lib/components/SubmissionStatusButton.svelte';
+  import SubmissionStatusButton from '#lib/components/SubmissionStatusButton.svelte';
 
-  import { getBackgroundColorFrom } from '$lib/services/submission_status';
+  import { getBackgroundColorFrom } from '#lib/services/submission_status.js';
 
-  import { getTaskGradeLabel, getTaskUrl } from '$lib/utils/task';
+  import { getTaskGradeLabel, getTaskUrl } from '#lib/utils/task.js';
 
   let { data } = $props();
 
diff --git a/src/routes/problems/page_server.test.ts b/src/routes/problems/page_server.test.ts
index 5394a8e30..81e69e83c 100644
--- a/src/routes/problems/page_server.test.ts
+++ b/src/routes/problems/page_server.test.ts
@@ -1,18 +1,18 @@
 import { describe, test, expect, vi, beforeEach } from 'vitest';
 
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 
 vi.mock('$features/votes/services/vote_statistics', () => ({
   getVoteGradeStatistics: vi.fn(),
 }));
 
-vi.mock('$lib/services/task_results', () => ({
+vi.mock('#lib/services/task_results.js', () => ({
   getTaskResults: vi.fn(),
   getTasksWithTagIds: vi.fn(),
 }));
 
 import * as voteStatsModule from '$features/votes/services/vote_statistics';
-import * as taskCrud from '$lib/services/task_results';
+import * as taskCrud from '#lib/services/task_results.js';
 import { load } from './+page.server';
 
 const mockGetVoteGradeStatistics = vi.mocked(voteStatsModule.getVoteGradeStatistics);
diff --git a/src/routes/sitemap.xml/+server.ts b/src/routes/sitemap.xml/+server.ts
index abcb5be4b..bc5272782 100644
--- a/src/routes/sitemap.xml/+server.ts
+++ b/src/routes/sitemap.xml/+server.ts
@@ -13,7 +13,7 @@ import * as sitemap from 'super-sitemap';
 import * as workBooksCrud from '$features/workbooks/services/workbooks';
 
 import { getUrlSlugFrom } from '$features/workbooks/utils/workbooks';
-import { INTERNAL_SERVER_ERROR } from '$lib/constants/http-response-status-codes';
+import { INTERNAL_SERVER_ERROR } from '#lib/constants/http-response-status-codes.js';
 
 /**
  * Handles the GET request to generate a sitemap.
diff --git a/src/routes/users/[username]/+page.server.ts b/src/routes/users/[username]/+page.server.ts
index 0078522c9..258330b7f 100644
--- a/src/routes/users/[username]/+page.server.ts
+++ b/src/routes/users/[username]/+page.server.ts
@@ -1,11 +1,11 @@
 //See https://tech-blog.rakus.co.jp/entry/20230209/sveltekit#%E3%82%B9%E3%83%AC%E3%83%83%E3%83%89%E6%8A%95%E7%A8%BF%E7%94%BB%E9%9D%A2
 
-import * as userService from '$lib/services/users';
-import * as taskResultService from '$lib/services/task_results';
+import * as userService from '#lib/services/users.js';
+import * as taskResultService from '#lib/services/task_results.js';
 import { getLoggedInUser } from '$features/auth/services/session_guards';
 
-import type { Roles } from '$lib/types/user';
-import type { TaskResult } from '$lib/types/task';
+import type { Roles } from '#lib/types/user.js';
+import type { TaskResult } from '#lib/types/task.js';
 
 export async function load({ locals, params, url }) {
   const loggedInUser = await getLoggedInUser(locals, url);
diff --git a/src/routes/users/[username]/+page.svelte b/src/routes/users/[username]/+page.svelte
index 459e1770e..9417a1c59 100644
--- a/src/routes/users/[username]/+page.svelte
+++ b/src/routes/users/[username]/+page.svelte
@@ -1,10 +1,10 @@
 <script lang="ts">
   import { resolve } from '$app/paths';
 
-  import UserProfile from '$lib/components/UserProfile.svelte';
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
-  import TaskListSorted from '$lib/components/TaskListSorted.svelte';
-  import { PROBLEMS_PAGE } from '$lib/constants/navbar-links';
+  import UserProfile from '#lib/components/UserProfile.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
+  import TaskListSorted from '#lib/components/TaskListSorted.svelte';
+  import { PROBLEMS_PAGE } from '#lib/constants/navbar-links.js';
 
   let { data } = $props();
 
diff --git a/src/routes/users/edit/+page.server.ts b/src/routes/users/edit/+page.server.ts
index b01be801d..d491ba0b8 100644
--- a/src/routes/users/edit/+page.server.ts
+++ b/src/routes/users/edit/+page.server.ts
@@ -2,9 +2,9 @@
 import { error, fail } from '@sveltejs/kit';
 
 import type { Actions } from './$types';
-import type { Roles } from '$lib/types/user';
+import type { Roles } from '#lib/types/user.js';
 
-import * as userService from '$lib/services/users';
+import * as userService from '#lib/services/users.js';
 import * as verificationService from '$features/account/services/atcoder_verification';
 import { getLoggedInUser } from '$features/auth/services/session_guards';
 
@@ -13,7 +13,7 @@ import {
   UNAUTHORIZED,
   FORBIDDEN,
   INTERNAL_SERVER_ERROR,
-} from '$lib/constants/http-response-status-codes';
+} from '#lib/constants/http-response-status-codes.js';
 
 export async function load({ locals, url }) {
   const loggedInUser = await getLoggedInUser(locals, url);
diff --git a/src/routes/users/edit/+page.svelte b/src/routes/users/edit/+page.svelte
index 5c0801366..9e4481454 100644
--- a/src/routes/users/edit/+page.svelte
+++ b/src/routes/users/edit/+page.svelte
@@ -3,11 +3,11 @@
 
   import AtCoderVerificationForm from '$features/account/components/settings/AtCoderVerificationForm.svelte';
   import AccountDeletionForm from '$features/account/components/delete/AccountDeletionForm.svelte';
-  import ContainerWrapper from '$lib/components/ContainerWrapper.svelte';
-  import FormWrapper from '$lib/components/FormWrapper.svelte';
-  import LabelWrapper from '$lib/components/LabelWrapper.svelte';
+  import ContainerWrapper from '#lib/components/ContainerWrapper.svelte';
+  import FormWrapper from '#lib/components/FormWrapper.svelte';
+  import LabelWrapper from '#lib/components/LabelWrapper.svelte';
 
-  import { Roles } from '$lib/types/user';
+  import { Roles } from '#lib/types/user.js';
 
   interface Props {
     data: {
diff --git a/src/routes/votes/+page.svelte b/src/routes/votes/+page.svelte
index 23538c2b5..bd32162ad 100644
--- a/src/routes/votes/+page.svelte
+++ b/src/routes/votes/+page.svelte
@@ -13,16 +13,16 @@
   import ExternalLink from '@lucide/svelte/icons/external-link';
   import FlaskConical from '@lucide/svelte/icons/flask-conical';
 
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
-  import GradeLabel from '$lib/components/GradeLabel.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
+  import GradeLabel from '#lib/components/GradeLabel.svelte';
   import RelativeEvaluationBadge from '$features/votes/components/RelativeEvaluationBadge.svelte';
 
-  import { TaskGrade } from '$lib/types/task';
+  import { TaskGrade } from '#lib/types/task.js';
   import { MIN_VOTES_FOR_PROVISIONAL_GRADE } from '$features/votes/constants/statistics';
 
-  import { getContestNameLabel } from '$lib/contests';
-  import { getTaskUrl, compareByContestIdAndTaskId } from '$lib/utils/task';
-  import { filterTasksBySearch } from '$lib/utils/task_filter';
+  import { getContestNameLabel } from '#lib/contests/index.js';
+  import { getTaskUrl, compareByContestIdAndTaskId } from '#lib/utils/task.js';
+  import { filterTasksBySearch } from '#lib/utils/task_filter.js';
   import { resolveDisplayGrade } from '$features/votes/utils/grade_options';
 
   const MAX_SEARCH_RESULTS = 20;
diff --git a/src/routes/votes/[slug]/+page.server.ts b/src/routes/votes/[slug]/+page.server.ts
index d52796cbc..023216952 100644
--- a/src/routes/votes/[slug]/+page.server.ts
+++ b/src/routes/votes/[slug]/+page.server.ts
@@ -3,7 +3,7 @@ import { superValidate } from 'sveltekit-superforms';
 import { zod4 } from 'sveltekit-superforms/adapters';
 import type { Actions, PageServerLoad } from './$types';
 
-import { getTask } from '$lib/services/tasks';
+import { getTask } from '#lib/services/tasks.js';
 import { getVoteGrade } from '$features/votes/services/vote_grade';
 import {
   getVoteCountersByTaskId,
@@ -11,7 +11,7 @@ import {
 } from '$features/votes/services/vote_statistics';
 import { voteAbsoluteGrade } from '$features/votes/actions/vote_actions';
 import { voteAbsoluteGradeSchema } from '$features/votes/zod/schema';
-import { BAD_REQUEST } from '$lib/constants/http-response-status-codes';
+import { BAD_REQUEST } from '#lib/constants/http-response-status-codes.js';
 
 export const load: PageServerLoad = async ({ locals, params }) => {
   const session = await locals.auth.validate();
diff --git a/src/routes/votes/[slug]/+page.svelte b/src/routes/votes/[slug]/+page.svelte
index 125246efc..42a8cd7d4 100644
--- a/src/routes/votes/[slug]/+page.svelte
+++ b/src/routes/votes/[slug]/+page.svelte
@@ -4,22 +4,22 @@
   import { page } from '$app/state';
   import { Button, Tooltip } from 'flowbite-svelte';
   import FlaskConical from '@lucide/svelte/icons/flask-conical';
-  import GradeLabel from '$lib/components/GradeLabel.svelte';
+  import GradeLabel from '#lib/components/GradeLabel.svelte';
   import RelativeEvaluationBadge from '$features/votes/components/RelativeEvaluationBadge.svelte';
 
-  import { TaskGrade } from '$lib/types/task';
+  import { TaskGrade } from '#lib/types/task.js';
   import {
     getTaskGradeLabel,
     getTaskUrl,
     getTaskGradeColor,
     toChangeTextColorIfNeeds,
-  } from '$lib/utils/task';
+  } from '#lib/utils/task.js';
 
   import VoteDonutChart from '$features/votes/components/VoteDonutChart.svelte';
   import { qGrades, dGrades } from '$features/votes/utils/grade_options';
   import { MIN_VOTES_FOR_PROVISIONAL_GRADE } from '$features/votes/constants/statistics';
 
-  import { EDIT_PROFILE_PAGE } from '$lib/constants/navbar-links';
+  import { EDIT_PROFILE_PAGE } from '#lib/constants/navbar-links.js';
   import { buildLoginPath } from '$features/auth/utils/login';
   import { buildSignupPath } from '$features/auth/utils/signup';
 
diff --git a/src/routes/votes/page_server.test.ts b/src/routes/votes/page_server.test.ts
index 640265409..4e1922afa 100644
--- a/src/routes/votes/page_server.test.ts
+++ b/src/routes/votes/page_server.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect, vi, beforeEach } from 'vitest';
 
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 
 vi.mock('$features/votes/services/vote_statistics', () => ({
   getAllTasksWithVoteInfo: vi.fn(),
diff --git a/src/routes/workbooks/+page.server.ts b/src/routes/workbooks/+page.server.ts
index 12b90c522..e36e8961a 100644
--- a/src/routes/workbooks/+page.server.ts
+++ b/src/routes/workbooks/+page.server.ts
@@ -1,7 +1,7 @@
 import { error, redirect } from '@sveltejs/kit';
 
-import * as taskCrud from '$lib/services/tasks';
-import * as taskResultsCrud from '$lib/services/task_results';
+import * as taskCrud from '#lib/services/tasks.js';
+import * as taskResultsCrud from '#lib/services/task_results.js';
 import { getLoggedInUser } from '$features/auth/services/session_guards';
 import * as workBooksCrud from '$features/workbooks/services/workbooks';
 import {
@@ -11,8 +11,8 @@ import {
   getSolutionCategoryMapByWorkbookId,
 } from '$features/workbooks/services/workbooks';
 
-import { Roles } from '$lib/types/user';
-import type { TaskGrade, TaskResult } from '$lib/types/task';
+import { Roles } from '#lib/types/user.js';
+import type { TaskGrade, TaskResult } from '#lib/types/task.js';
 import {
   WorkBookTab,
   type WorkBookTab as WorkBookTabType,
@@ -25,7 +25,7 @@ import {
   type SolutionCategory,
 } from '$features/workbooks/types/workbook_placement';
 
-import { isAdmin, canDelete } from '$lib/utils/authorship';
+import { isAdmin, canDelete } from '#lib/utils/authorship.js';
 import { buildTaskIdsFromWorkbooks } from '$features/workbooks/utils/workbooks';
 import {
   parseWorkBookTab,
@@ -40,7 +40,7 @@ import {
   FOUND,
   NOT_FOUND,
   INTERNAL_SERVER_ERROR,
-} from '$lib/constants/http-response-status-codes';
+} from '#lib/constants/http-response-status-codes.js';
 
 export async function load({ locals, url }) {
   const loggedInUser = await getLoggedInUser(locals, url);
diff --git a/src/routes/workbooks/+page.svelte b/src/routes/workbooks/+page.svelte
index 8120d574d..9e2fa42c6 100644
--- a/src/routes/workbooks/+page.svelte
+++ b/src/routes/workbooks/+page.svelte
@@ -5,9 +5,9 @@
 
   import { Button, Tabs } from 'flowbite-svelte';
 
-  import { Roles } from '$lib/types/user';
-  import { isAdmin } from '$lib/utils/authorship';
-  import { type Task, TaskGrade, type TaskResult } from '$lib/types/task';
+  import { Roles } from '#lib/types/user.js';
+  import { isAdmin } from '#lib/utils/authorship.js';
+  import { type Task, TaskGrade, type TaskResult } from '#lib/types/task.js';
   import {
     type WorkbooksList,
     WorkBookType,
@@ -15,7 +15,7 @@
   } from '$features/workbooks/types/workbook';
   import { type SelectedSolutionCategory } from '$features/workbooks/types/workbook_placement';
 
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
   import WorkbookTabItem from '$features/workbooks/components/list/WorkbookTabItem.svelte';
   import WorkBookList from '$features/workbooks/components/list/WorkBookList.svelte';
 
diff --git a/src/routes/workbooks/[slug]/+page.server.ts b/src/routes/workbooks/[slug]/+page.server.ts
index c32ba7c07..85ad4d9d6 100644
--- a/src/routes/workbooks/[slug]/+page.server.ts
+++ b/src/routes/workbooks/[slug]/+page.server.ts
@@ -2,20 +2,20 @@ import { error, fail, type Actions } from '@sveltejs/kit';
 import { superValidate } from 'sveltekit-superforms';
 import { zod4 } from 'sveltekit-superforms/adapters';
 
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 
 import { getLoggedInUser } from '$features/auth/services/session_guards';
-import * as taskResultsCrud from '$lib/services/task_results';
-import * as action from '$lib/actions/update_task_result';
+import * as taskResultsCrud from '#lib/services/task_results.js';
+import * as action from '#lib/actions/update_task_result.js';
 import { getWorkbookWithAuthor } from '$features/workbooks/services/workbooks';
 import { getVoteGradeStatisticsForTaskIds } from '$features/votes/services/vote_statistics';
 import { voteAbsoluteGrade as voteAbsoluteGradeAction } from '$features/votes/actions/vote_actions';
 import { voteAbsoluteGradeSchema } from '$features/votes/zod/schema';
 
-import { isAdmin, canRead } from '$lib/utils/authorship';
+import { isAdmin, canRead } from '#lib/utils/authorship.js';
 import { parseWorkBookId, parseWorkBookUrlSlug } from '$features/workbooks/utils/workbook';
 
-import { BAD_REQUEST, FORBIDDEN, NOT_FOUND } from '$lib/constants/http-response-status-codes';
+import { BAD_REQUEST, FORBIDDEN, NOT_FOUND } from '#lib/constants/http-response-status-codes.js';
 
 export async function load({ locals, params, url }) {
   const loggedInUser = await getLoggedInUser(locals, url);
diff --git a/src/routes/workbooks/[slug]/+page.svelte b/src/routes/workbooks/[slug]/+page.svelte
index d4659fe1b..1dd083789 100644
--- a/src/routes/workbooks/[slug]/+page.svelte
+++ b/src/routes/workbooks/[slug]/+page.svelte
@@ -10,20 +10,20 @@
     TableBodyRow,
   } from 'flowbite-svelte';
 
-  import CompletedTasks from '$lib/components/Trophies/CompletedTasks.svelte';
-  import HeadingOne from '$lib/components/HeadingOne.svelte';
-  import UpdatingModal from '$lib/components/SubmissionStatus/UpdatingModal.svelte';
-  import SubmissionStatusImage from '$lib/components/SubmissionStatus/SubmissionStatusImage.svelte';
-  import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
+  import CompletedTasks from '#lib/components/Trophies/CompletedTasks.svelte';
+  import HeadingOne from '#lib/components/HeadingOne.svelte';
+  import UpdatingModal from '#lib/components/SubmissionStatus/UpdatingModal.svelte';
+  import SubmissionStatusImage from '#lib/components/SubmissionStatus/SubmissionStatusImage.svelte';
+  import ExternalLinkWrapper from '#lib/components/ExternalLinkWrapper.svelte';
   import VotableGrade from '$features/votes/components/VotableGrade.svelte';
   import PublicationStatusLabel from '$features/workbooks/components/shared/PublicationStatusLabel.svelte';
   import CommentAndHint from '$features/workbooks/components/detail/CommentAndHint.svelte';
-  import { getBackgroundColorFrom } from '$lib/services/submission_status';
+  import { getBackgroundColorFrom } from '#lib/services/submission_status.js';
 
-  import { addContestNameToTaskIndex } from '$lib/contests';
-  import { getTaskUrl, removeTaskIndexFromTitle } from '$lib/utils/task';
+  import { addContestNameToTaskIndex } from '#lib/contests/index.js';
+  import { getTaskUrl, removeTaskIndexFromTitle } from '#lib/utils/task.js';
 
-  import type { TaskResult } from '$lib/types/task';
+  import type { TaskResult } from '#lib/types/task.js';
   import type { WorkBookTaskBase } from '$features/workbooks/types/workbook';
 
   let { data } = $props();
diff --git a/src/routes/workbooks/create/+page.server.ts b/src/routes/workbooks/create/+page.server.ts
index 81f6d57ba..6f602bf9e 100644
--- a/src/routes/workbooks/create/+page.server.ts
+++ b/src/routes/workbooks/create/+page.server.ts
@@ -2,18 +2,18 @@ import { error, fail, redirect } from '@sveltejs/kit';
 import { superValidate } from 'sveltekit-superforms/server';
 import { zod4 } from 'sveltekit-superforms/adapters';
 
-import * as tasksCrud from '$lib/services/tasks';
+import * as tasksCrud from '#lib/services/tasks.js';
 import { ensureSessionOrRedirect, getLoggedInUser } from '$features/auth/services/session_guards';
 import * as workBooksCrud from '$features/workbooks/services/workbooks';
 import { workBookSchema } from '$features/workbooks/zod/schema';
 
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 
 import {
   BAD_REQUEST,
   FORBIDDEN,
   TEMPORARY_REDIRECT,
-} from '$lib/constants/http-response-status-codes';
+} from '#lib/constants/http-response-status-codes.js';
 
 export const load = async ({ locals, url }) => {
   await ensureSessionOrRedirect(locals, url);
diff --git a/src/routes/workbooks/create/+page.svelte b/src/routes/workbooks/create/+page.svelte
index b34a7b906..46793abf8 100644
--- a/src/routes/workbooks/create/+page.svelte
+++ b/src/routes/workbooks/create/+page.svelte
@@ -1,7 +1,7 @@
 <script lang="ts">
   import { superForm } from 'sveltekit-superforms/client';
 
-  import type { Task } from '$lib/types/task';
+  import type { Task } from '#lib/types/task.js';
   import { WorkBookType, type WorkBookTasksBase } from '$features/workbooks/types/workbook';
 
   import WorkBookForm from '$features/workbooks/components/shared/WorkBookForm.svelte';
diff --git a/src/routes/workbooks/edit/[slug]/+page.server.ts b/src/routes/workbooks/edit/[slug]/+page.server.ts
index 79065edea..3eed6841d 100644
--- a/src/routes/workbooks/edit/[slug]/+page.server.ts
+++ b/src/routes/workbooks/edit/[slug]/+page.server.ts
@@ -2,14 +2,14 @@ import { error, redirect, fail } from '@sveltejs/kit';
 import { superValidate } from 'sveltekit-superforms/server';
 import { zod4 } from 'sveltekit-superforms/adapters';
 
-import { Roles } from '$lib/types/user';
+import { Roles } from '#lib/types/user.js';
 import { workBookSchema } from '$features/workbooks/zod/schema';
 
-import * as tasksCrud from '$lib/services/tasks';
+import * as tasksCrud from '#lib/services/tasks.js';
 import { getLoggedInUser } from '$features/auth/services/session_guards';
 import * as workBooksCrud from '$features/workbooks/services/workbooks';
 
-import { canEdit, isAdmin } from '$lib/utils/authorship';
+import { canEdit, isAdmin } from '#lib/utils/authorship.js';
 import { parseWorkBookId, parseWorkBookUrlSlug } from '$features/workbooks/utils/workbook';
 
 import {
@@ -18,7 +18,7 @@ import {
   NOT_FOUND,
   TEMPORARY_REDIRECT,
   INTERNAL_SERVER_ERROR,
-} from '$lib/constants/http-response-status-codes';
+} from '#lib/constants/http-response-status-codes.js';
 
 export async function load({ locals, params, url }) {
   const loggedInUser = await getLoggedInUser(locals, url);
diff --git a/src/routes/workbooks/edit/[slug]/+page.svelte b/src/routes/workbooks/edit/[slug]/+page.svelte
index e4cebffb6..7935f4aaa 100644
--- a/src/routes/workbooks/edit/[slug]/+page.svelte
+++ b/src/routes/workbooks/edit/[slug]/+page.svelte
@@ -1,14 +1,14 @@
 <script lang="ts">
   import { superForm } from 'sveltekit-superforms/client';
 
-  import ErrorMessageAndReturnButton from '$lib/components/Messages/ErrorMessageAndReturnButton.svelte';
+  import ErrorMessageAndReturnButton from '#lib/components/Messages/ErrorMessageAndReturnButton.svelte';
   import WorkBookForm from '$features/workbooks/components/shared/WorkBookForm.svelte';
 
-  import type { Task } from '$lib/types/task.js';
+  import type { Task } from '#lib/types/task.js';
   import type { WorkBookTasksBase } from '$features/workbooks/types/workbook';
 
-  import { FORBIDDEN } from '$lib/constants/http-response-status-codes.js';
-  import { WORKBOOKS_PAGE } from '$lib/constants/navbar-links';
+  import { FORBIDDEN } from '#lib/constants/http-response-status-codes.js';
+  import { WORKBOOKS_PAGE } from '#lib/constants/navbar-links.js';
 
   let { data } = $props();
   let canView = $derived(data.status === FORBIDDEN ? false : true);
diff --git a/src/test/lib/services/fixtures/task_results.ts b/src/test/lib/services/fixtures/task_results.ts
index cd17bee92..86b096e72 100644
--- a/src/test/lib/services/fixtures/task_results.ts
+++ b/src/test/lib/services/fixtures/task_results.ts
@@ -1,5 +1,5 @@
-import { ContestType } from '$lib/contests/types/contest';
-import { TaskGrade } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import { TaskGrade } from '#lib/types/task.js';
 
 type MockedSubmissionStatus = {
   id: string;
diff --git a/src/test/lib/services/task_results.test.ts b/src/test/lib/services/task_results.test.ts
index 23aca1c3d..08a514c26 100644
--- a/src/test/lib/services/task_results.test.ts
+++ b/src/test/lib/services/task_results.test.ts
@@ -12,11 +12,11 @@
 
 import { describe, test, expect, vi, beforeEach } from 'vitest';
 
-import { getTasks } from '$lib/services/tasks';
-import { getAnswers } from '$lib/services/answers';
-import { getTaskResults, getTaskResultsOnlyResultExists } from '$lib/services/task_results';
+import { getTasks } from '#lib/services/tasks.js';
+import { getAnswers } from '#lib/services/answers.js';
+import { getTaskResults, getTaskResultsOnlyResultExists } from '#lib/services/task_results.js';
 
-import type { TaskResult, TaskResults, Tasks } from '$lib/types/task';
+import type { TaskResult, TaskResults, Tasks } from '#lib/types/task.js';
 
 import {
   MOCK_TASKS_DATA,
@@ -28,11 +28,11 @@ import {
 // Note: Vitest's vi.mock() factory functions are hoisted before module initialization,
 // so we cannot import constants from fixtures directly. However, the mock data below
 // corresponds to MOCK_SUBMISSION_STATUSES_DATA in ./fixtures/task_results.ts
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {},
 }));
 
-vi.mock('$lib/services/submission_status', () => ({
+vi.mock('#lib/services/submission_status.js', () => ({
   getSubmissionStatusMapWithId: vi.fn().mockResolvedValue(
     new Map([
       [
@@ -80,7 +80,7 @@ vi.mock('$lib/services/submission_status', () => ({
   getSubmissionStatusMapWithName: vi.fn().mockResolvedValue(new Map()),
 }));
 
-vi.mock('$lib/services/tasks', () => {
+vi.mock('#lib/services/tasks.js', () => {
   // Note: Mock data corresponds to MOCK_TASKS_DATA in ./fixtures/task_results.ts
   const mockTasksData = [
     {
@@ -315,13 +315,13 @@ vi.mock('$lib/services/tasks', () => {
   };
 });
 
-vi.mock('$lib/services/users', () => ({
+vi.mock('#lib/services/users.js', () => ({
   getUser: vi.fn(),
 }));
 
 let mockAnswersForTest = new Map();
 
-vi.mock('$lib/services/answers', () => ({
+vi.mock('#lib/services/answers.js', () => ({
   getAnswers: vi.fn(async () => mockAnswersForTest),
   getAnswersWithSelectedTaskIds: vi.fn(),
   getAnswer: vi.fn(),
diff --git a/src/test/lib/services/tasks.test.ts b/src/test/lib/services/tasks.test.ts
index 4cb6c67ea..7267b6833 100644
--- a/src/test/lib/services/tasks.test.ts
+++ b/src/test/lib/services/tasks.test.ts
@@ -2,10 +2,10 @@ import { describe, test, expect, vi } from 'vitest';
 
 import { Prisma } from '@prisma/client';
 
-import { TaskGrade } from '$lib/types/task';
-import { updateTask } from '$lib/services/tasks';
+import { TaskGrade } from '#lib/types/task.js';
+import { updateTask } from '#lib/services/tasks.js';
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     task: {
       update: vi.fn(),
@@ -13,7 +13,7 @@ vi.mock('$lib/server/database', () => ({
   },
 }));
 
-vi.mock('$lib/server/tasks/cache', () => ({
+vi.mock('#lib/server/tasks/cache.js', () => ({
   getCachedTasksMap: (fetchFn: () => Promise<unknown>) => fetchFn(),
   getCachedMergedTasksMap: (fetchFn: () => Promise<unknown>) => fetchFn(),
   invalidateTaskCaches: vi.fn(),
@@ -23,7 +23,7 @@ vi.mock('$features/votes/server/cache', () => ({
   invalidateVoteCaches: vi.fn(),
 }));
 
-import db from '$lib/server/database';
+import db from '#lib/server/database.js';
 import { invalidateVoteCaches } from '$features/votes/server/cache';
 
 describe('updateTask', () => {
diff --git a/src/test/lib/services/users.test.ts b/src/test/lib/services/users.test.ts
index ac09732b8..31f9479ce 100644
--- a/src/test/lib/services/users.test.ts
+++ b/src/test/lib/services/users.test.ts
@@ -1,7 +1,7 @@
 import { describe, test, expect, vi } from 'vitest';
 import { Roles, type User } from '@prisma/client';
 
-vi.mock('$lib/server/database', () => ({
+vi.mock('#lib/server/database.js', () => ({
   default: {
     user: {
       findUnique: vi.fn(),
@@ -10,8 +10,8 @@ vi.mock('$lib/server/database', () => ({
   },
 }));
 
-import db from '$lib/server/database';
-import { getUser, getUserById, deleteUser } from '$lib/services/users';
+import db from '#lib/server/database.js';
+import { getUser, getUserById, deleteUser } from '#lib/services/users.js';
 
 // ---------------------------------------------------------------------------
 // Type aliases
diff --git a/src/test/lib/stores/active_problem_list_tab.svelte.test.ts b/src/test/lib/stores/active_problem_list_tab.svelte.test.ts
index 288edc478..99f0da1c7 100644
--- a/src/test/lib/stores/active_problem_list_tab.svelte.test.ts
+++ b/src/test/lib/stores/active_problem_list_tab.svelte.test.ts
@@ -5,7 +5,7 @@ import { describe, test, expect, vi, beforeEach, afterEach } from 'vitest';
 import {
   activeProblemListTabStore,
   ActiveProblemListTabStore,
-} from '$lib/stores/active_problem_list_tab.svelte';
+} from '#lib/stores/active_problem_list_tab.svelte.js';
 
 // WHY: a single dynamic mock is the only way to toggle `browser` per describe. Every vi.mock is
 // hoisted and the last registration for a module wins, so a second vi.mock of `$app/environment`
diff --git a/src/test/lib/utils/account_transfer.test.ts b/src/test/lib/utils/account_transfer.test.ts
index 09b8cc993..3f38e9cf8 100644
--- a/src/test/lib/utils/account_transfer.test.ts
+++ b/src/test/lib/utils/account_transfer.test.ts
@@ -6,9 +6,9 @@ import {
   validateUserAnswersTransferability,
   isExistingUser,
   isAdminUser,
-} from '$lib/utils/account_transfer';
+} from '#lib/utils/account_transfer.js';
 
-import type { FloatingMessages } from '$lib/types/floating_message';
+import type { FloatingMessages } from '#lib/types/floating_message.js';
 
 import {
   type TestCaseForTransferValidation,
diff --git a/src/test/lib/utils/auth_forms.test.ts b/src/test/lib/utils/auth_forms.test.ts
index 305646209..049116d80 100644
--- a/src/test/lib/utils/auth_forms.test.ts
+++ b/src/test/lib/utils/auth_forms.test.ts
@@ -23,7 +23,7 @@ vi.mock('sveltekit-superforms/adapters', () => ({
   zod4: vi.fn(),
 }));
 
-vi.mock('$lib/zod/schema', () => ({
+vi.mock('#lib/zod/schema.js', () => ({
   authSchema: {
     _type: 'ZodObject',
     shape: {
@@ -33,11 +33,11 @@ vi.mock('$lib/zod/schema', () => ({
   },
 }));
 
-vi.mock('$lib/constants/http-response-status-codes', () => ({
+vi.mock('#lib/constants/http-response-status-codes.js', () => ({
   SEE_OTHER: 303,
 }));
 
-vi.mock('$lib/constants/navbar-links', () => ({
+vi.mock('#lib/constants/navbar-links.js', () => ({
   HOME_PAGE: '/',
 }));
 
@@ -50,7 +50,7 @@ import {
   initializeAuthForm,
   createAuthFormWithFallback,
   validateAuthFormWithFallback,
-} from '$lib/utils/auth_forms';
+} from '#lib/utils/auth_forms.js';
 
 // Mock console methods
 const mockConsoleWarn = vi.fn();
diff --git a/src/test/lib/utils/contest_task_pair.test.ts b/src/test/lib/utils/contest_task_pair.test.ts
index 8b9f83150..9e88eae4e 100644
--- a/src/test/lib/utils/contest_task_pair.test.ts
+++ b/src/test/lib/utils/contest_task_pair.test.ts
@@ -1,6 +1,6 @@
 import { describe, test, expect } from 'vitest';
 
-import { createContestTaskPairKey } from '$lib/utils/contest_task_pair';
+import { createContestTaskPairKey } from '#lib/utils/contest_task_pair.js';
 
 describe('createContestTaskPairKey', () => {
   // Test data structure
diff --git a/src/test/lib/utils/html.test.ts b/src/test/lib/utils/html.test.ts
index 650503d2c..64379401e 100644
--- a/src/test/lib/utils/html.test.ts
+++ b/src/test/lib/utils/html.test.ts
@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { sanitizeHTML } from '$lib/utils/html';
+import { sanitizeHTML } from '#lib/utils/html.js';
 
 describe('sanitizeHTML', () => {
   it('expects to be removed dangerous HTML', () => {
diff --git a/src/test/lib/utils/task.test.ts b/src/test/lib/utils/task.test.ts
index 8e8a3144e..efd1546b5 100644
--- a/src/test/lib/utils/task.test.ts
+++ b/src/test/lib/utils/task.test.ts
@@ -13,8 +13,8 @@ import {
 } from './test_cases/task_results';
 import { taskResultsForTaskTableHeaderName } from './test_cases/task_table_header_name';
 
-import { ContestType } from '$lib/contests/types/contest';
-import { type TaskResult, type TaskResults } from '$lib/types/task';
+import { ContestType } from '#lib/contests/types/contest.js';
+import { type TaskResult, type TaskResults } from '#lib/types/task.js';
 import type { WorkBookTaskBase } from '$features/workbooks/types/workbook';
 
 import {
@@ -25,7 +25,7 @@ import {
   compareByContestIdAndTaskId,
   removeTaskIndexFromTitle,
   getTaskTableHeaderName,
-} from '$lib/utils/task';
+} from '#lib/utils/task.js';
 
 type TestCaseForTaskResults = {
   taskResults: TaskResults;
diff --git a/src/test/lib/utils/task_filter.test.ts b/src/test/lib/utils/task_filter.test.ts
index 514addb08..9dd5982d8 100644
--- a/src/test/lib/utils/task_filter.test.ts
+++ b/src/test/lib/utils/task_filter.test.ts
@@ -1,5 +1,5 @@
 import { describe, test, expect } from 'vitest';
-import { filterTasksBySearch } from '$lib/utils/task_filter';
+import { filterTasksBySearch } from '#lib/utils/task_filter.js';
 
 const tasks = [
   { title: 'ABC 300 A - N-choice question', task_id: 'abc300_a', contest_id: 'abc300' },
diff --git a/src/test/lib/utils/task_grade.test.ts b/src/test/lib/utils/task_grade.test.ts
index 8c659939e..24b7ebe0f 100644
--- a/src/test/lib/utils/task_grade.test.ts
+++ b/src/test/lib/utils/task_grade.test.ts
@@ -8,9 +8,9 @@ import {
   getTaskGradeLabel,
   toChangeTextColorIfNeeds,
   toChangeBorderColorIfNeeds,
-} from '$lib/utils/task';
+} from '#lib/utils/task.js';
 
-import { TaskGrade, type TaskGrades } from '$lib/types/task';
+import { TaskGrade, type TaskGrades } from '#lib/types/task.js';
 
 type TestCaseForTaskGradeOrder = {
   taskGrade: TaskGrade;
diff --git a/src/test/lib/utils/test_cases/account_transfer.ts b/src/test/lib/utils/test_cases/account_transfer.ts
index a5ad17b86..9caa9924e 100644
--- a/src/test/lib/utils/test_cases/account_transfer.ts
+++ b/src/test/lib/utils/test_cases/account_transfer.ts
@@ -1,7 +1,7 @@
 import type { User } from '@prisma/client';
-import { Roles } from '$lib/types/user';
-import type { TaskResult } from '$lib/types/task';
-import type { FloatingMessages } from '$lib/types/floating_message';
+import { Roles } from '#lib/types/user.js';
+import type { TaskResult } from '#lib/types/task.js';
+import type { FloatingMessages } from '#lib/types/floating_message.js';
 
 import { createTestCase } from '../../common/test_helpers';
 import { taskResultsForUserId3 } from './task_results';
diff --git a/src/test/lib/utils/test_cases/task_results.ts b/src/test/lib/utils/test_cases/task_results.ts
index 253ce4393..0ae90db05 100644
--- a/src/test/lib/utils/test_cases/task_results.ts
+++ b/src/test/lib/utils/test_cases/task_results.ts
@@ -1,5 +1,5 @@
-import { TaskGrade } from '$lib/types/task';
-import type { TaskResult, TaskResults } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
+import type { TaskResult, TaskResults } from '#lib/types/task.js';
 import type { WorkBookTaskBase } from '$features/workbooks/types/workbook';
 
 const userId2 = '2';
diff --git a/src/test/lib/utils/test_cases/task_table_header_name.ts b/src/test/lib/utils/test_cases/task_table_header_name.ts
index dfe45767d..b406bc2f1 100644
--- a/src/test/lib/utils/test_cases/task_table_header_name.ts
+++ b/src/test/lib/utils/test_cases/task_table_header_name.ts
@@ -1,5 +1,5 @@
-import { TaskGrade } from '$lib/types/task';
-import type { TaskResult } from '$lib/types/task';
+import { TaskGrade } from '#lib/types/task.js';
+import type { TaskResult } from '#lib/types/task.js';
 
 // Default task result with minimal initialization.
 // Most fields are empty strings as they're not relevant for these tests.
diff --git a/src/test/lib/utils/test_cases/task_url.ts b/src/test/lib/utils/test_cases/task_url.ts
index 79fa865f5..4a7bf2a83 100644
--- a/src/test/lib/utils/test_cases/task_url.ts
+++ b/src/test/lib/utils/test_cases/task_url.ts
@@ -1,6 +1,6 @@
 import { createTestCase } from '../../common/test_helpers';
 
-import { ATCODER_BASE_CONTEST_URL, AOJ_TASKS_URL } from '$lib/constants/urls';
+import { ATCODER_BASE_CONTEST_URL, AOJ_TASKS_URL } from '#lib/constants/urls.js';
 
 /** Represents a test case for task URL generation.
  *
diff --git a/src/test/lib/utils/time.test.ts b/src/test/lib/utils/time.test.ts
index 5d1c4fb76..3908754d4 100644
--- a/src/test/lib/utils/time.test.ts
+++ b/src/test/lib/utils/time.test.ts
@@ -1,5 +1,5 @@
 import { describe, it, expect } from 'vitest';
-import { delay } from '$lib/utils/time';
+import { delay } from '#lib/utils/time.js';
 
 describe('Delay', () => {
   it('expected to be resolved after the specified delay', async () => {
diff --git a/src/test/lib/utils/url.test.ts b/src/test/lib/utils/url.test.ts
index a515b321f..75171626d 100644
--- a/src/test/lib/utils/url.test.ts
+++ b/src/test/lib/utils/url.test.ts
@@ -1,6 +1,6 @@
 import { expect, test } from 'vitest';
 
-import { isValidUrl, isValidUrlSlug, sanitizeUrl } from '$lib/utils/url';
+import { isValidUrl, isValidUrlSlug, sanitizeUrl } from '#lib/utils/url.js';
 
 type TestCaseForUrlValidation = {
   rawUrl: string;
diff --git a/src/test/lib/zod/account_transfer_schema.test.ts b/src/test/lib/zod/account_transfer_schema.test.ts
index 63060a814..c267ffa8b 100644
--- a/src/test/lib/zod/account_transfer_schema.test.ts
+++ b/src/test/lib/zod/account_transfer_schema.test.ts
@@ -1,7 +1,7 @@
 import { expect, test } from 'vitest';
 import { type ZodSchema } from 'zod';
 
-import { accountTransferSchema } from '$lib/zod/schema';
+import { accountTransferSchema } from '#lib/zod/schema.js';
 
 describe('Account Transfer schema', () => {
   describe('Correct source and destination user are given', () => {
diff --git a/src/test/lib/zod/auth_schema.test.ts b/src/test/lib/zod/auth_schema.test.ts
index 839ab87c3..7ac7e12ba 100644
--- a/src/test/lib/zod/auth_schema.test.ts
+++ b/src/test/lib/zod/auth_schema.test.ts
@@ -1,7 +1,7 @@
 import { expect, test } from 'vitest';
 import { type ZodSchema } from 'zod';
 
-import { authSchema } from '$lib/zod/schema';
+import { authSchema } from '#lib/zod/schema.js';
 
 describe('Auth schema', () => {
   describe('a correct user is given', () => {