Refactor samples into an accessible static learning gallery

.editorconfig

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+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false

.gitattributes

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+* text=auto eol=lf
+
+*.jpg binary
+*.jpeg binary
+*.png binary
+*.webp binary

.github/dependabot.yml

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+version: 2
+
+updates:
+  - package-ecosystem: npm
+    directory: /
+    schedule:
+      interval: monthly
+      day: monday
+      time: "03:00"
+      timezone: Asia/Shanghai
+    open-pull-requests-limit: 5
+    groups:
+      development-dependencies:
+        dependency-type: development
+        patterns:
+          - "*"
+    commit-message:
+      prefix: chore
+      include: scope
+    labels:
+      - dependencies
+
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: monthly
+      day: monday
+      time: "03:30"
+      timezone: Asia/Shanghai
+    open-pull-requests-limit: 5
+    groups:
+      github-actions:
+        patterns:
+          - "*"
+    commit-message:
+      prefix: chore
+      include: scope
+    labels:
+      - dependencies

.github/workflows/ci.yml

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+name: Verify and deploy
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: html-sample-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  validate:
+    name: Validate (${{ matrix.os }})
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+          - windows-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@fbc6f3992d24b796d5a048ff273f7fcc4a7b6c09 # v5
+
+      - name: Set up Node.js
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
+        with:
+          node-version: 24
+          cache: npm
+
+      - name: Install locked dependencies
+        run: npm ci
+
+      - name: Run static checks
+        run: npm run check
+
+      - name: Run unit tests
+        run: npm run test:unit
+
+      - name: Audit high-severity dependencies
+        run: npm audit --audit-level=high
+
+  browser-linux:
+    name: Browser tests (Ubuntu)
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@fbc6f3992d24b796d5a048ff273f7fcc4a7b6c09 # v5
+
+      - name: Set up Node.js
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
+        with:
+          node-version: 24
+          cache: npm
+
+      - name: Install locked dependencies
+        run: npm ci
+
+      - name: Install browser engines
+        run: npx playwright install --with-deps chromium firefox webkit
+
+      - name: Run Linux browser and visual tests
+        run: npm run test:e2e:linux
+
+      - name: Upload browser diagnostics
+        if: failure()
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
+        with:
+          name: playwright-ubuntu
+          path: test-results/
+          if-no-files-found: ignore
+          retention-days: 7
+
+  browser-windows:
+    name: Browser tests (Windows)
+    runs-on: windows-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@fbc6f3992d24b796d5a048ff273f7fcc4a7b6c09 # v5
+
+      - name: Set up Node.js
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
+        with:
+          node-version: 24
+          cache: npm
+
+      - name: Install locked dependencies
+        run: npm.cmd ci
+
+      - name: Install browser engines
+        run: npx.cmd playwright install chromium firefox
+
+      - name: Run Windows browser tests
+        run: npm.cmd run test:e2e:windows
+
+      - name: Upload browser diagnostics
+        if: failure()
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
+        with:
+          name: playwright-windows
+          path: test-results/
+          if-no-files-found: ignore
+          retention-days: 7
+
+  lighthouse:
+    name: Lighthouse budgets
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@fbc6f3992d24b796d5a048ff273f7fcc4a7b6c09 # v5
+
+      - name: Set up Node.js
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
+        with:
+          node-version: 24
+          cache: npm
+
+      - name: Install locked dependencies
+        run: npm ci
+
+      - name: Run Lighthouse
+        run: npm run test:lighthouse
+
+      - name: Upload Lighthouse reports
+        if: always()
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
+        with:
+          name: lighthouse
+          path: test-results/lighthouse/
+          if-no-files-found: ignore
+          retention-days: 7
+
+  deploy:
+    name: Deploy GitHub Pages
+    if: github.event_name == 'push' && github.ref == 'refs/heads/master'
+    needs:
+      - validate
+      - browser-linux
+      - browser-windows
+      - lighthouse
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    permissions:
+      contents: read
+      id-token: write
+      pages: write
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@fbc6f3992d24b796d5a048ff273f7fcc4a7b6c09 # v5
+
+      - name: Set up Node.js
+        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4
+        with:
+          node-version: 24
+          cache: npm
+
+      - name: Install locked dependencies
+        run: npm ci
+
+      - name: Build publish directory
+        run: npm run build
+
+      - name: Configure Pages
+        uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5
+        with:
+          enablement: true
+
+      - name: Upload Pages artifact
+        uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3
+        with:
+          path: _site
+
+      - name: Deploy Pages
+        id: deployment
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4

.gitignore

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+node_modules/
+_site/
+test-results/
+playwright-report/
+.lighthouseci/
+
+.DS_Store
+Thumbs.db
+*.log

.htmlvalidate.json

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+{
+  "extends": ["html-validate:recommended"],
+  "rules": {
+    "attribute-boolean-style": ["error", { "style": "omit" }],
+    "attribute-empty-style": ["error", { "style": "omit" }],
+    "doctype-style": ["error", { "style": "lowercase" }],
+    "no-inline-style": "error",
+    "no-redundant-role": "error",
+    "prefer-native-element": "error",
+    "void-style": ["error", { "style": "selfclosing" }],
+    "wcag/h30": "error",
+    "wcag/h32": "error",
+    "wcag/h37": "error",
+    "wcag/h63": "error",
+    "wcag/h71": "error"
+  }
+}

.nvmrc

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+24

.prettierignore

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+node_modules/
+_site/
+test-results/
+playwright-report/
+.lighthouseci/
+
+assignment-1 2/css/Mutual evaluation.css
+assignment-1 2/css/hw1 - old.css
+assignment-1 2/css/hw1 - old2.css

CHANGELOG.md

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+# Changelog
+
+All notable changes to this project are documented here.
+
+## [Unreleased]
+
+### Added
+
+- Unified bilingual gallery entry point.
+- Accessible Learning Profile, Ultimate Field Notes, and Signal Conference examples.
+- Zero-data registration form demonstration.
+- Windows and Ubuntu CI, browser tests, visual snapshots, accessibility checks, and Lighthouse budgets.
+- GitHub Pages deployment workflow and project documentation.
+
+### Changed
+
+- Replaced remote and unverified media with locally owned artwork.
+- Rewrote course-derived copy and demo data with original content.
+- Preserved every historical public path while modernizing active pages.

CONTRIBUTING.md

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+# Contributing
+
+## Requirements
+
+- Node.js 24 LTS
+- npm supplied with Node.js
+- Current Chrome, Edge, and Firefox on Windows for the full local matrix
+
+Do not change Windows execution policy or environment variables for this project. In PowerShell, use `npm.cmd` when `npm.ps1` is disabled.
+
+## Workflow
+
+1. Create a focused branch from `master`.
+2. Install exactly from the lockfile with `npm.cmd ci`.
+3. Keep all existing compatibility paths available.
+4. Add or update tests under `test/`.
+5. Run the complete relevant test set before committing.
+6. Open a pull request and wait for Windows and Ubuntu checks to pass.
+
+## Required checks
+
+```powershell
+npm.cmd run check
+npm.cmd run test:unit
+npm.cmd run test:e2e:windows
+npm.cmd run test:lighthouse
+npm.cmd run build
+```
+
+Ubuntu CI additionally runs Chromium, Firefox, WebKit, mobile Chromium, and the committed screenshot baselines.
+
+## Visual snapshots
+
+Stable baselines live in `test/snapshots/`. Normal tests never overwrite them. Update them only after reviewing the visual change:
+
+```powershell
+npm.cmd run test:visual:update
+```
+
+Generated reports, failure screenshots, traces, and videos belong in `test-results/` and must not be committed.
+
+## Content and privacy
+
+- Use original copy and locally owned or clearly licensed assets.
+- Record any third-party material in `THIRD_PARTY_NOTICES.md`.
+- Do not add analytics, remote fonts, tracking pixels, form endpoints, cookies, or browser storage.
+- Keep external links deliberate, HTTPS-only, and limited to authoritative references.
+
+## HTML and accessibility
+
+- Preserve landmark and heading order.
+- Provide visible keyboard focus.
+- Use native elements before ARIA.
+- Give every form control a persistent label and useful error message.
+- Verify layouts at 200% zoom and with Windows forced colors.
+- Update `test/manual-accessibility.md` when behavior changes materially.