- Remove jQuery (84KB) - all functionality now vanilla JS
- Remove legacy google-analytics.j2 (using gtag v4 instead)
- Remove ie8.polyfils.min.js (IE8 is dead)
- Add X-Requested-With header for AJAX preview requests
- Textareas auto-grow up to 400px as content is added
- Auto-grow triggers on toggle open if textarea has content
- Use CSS keyframes (slideDown/slideUp) for 800ms door-like animations
- JS only toggles classes and updates button text at correct timing
- Preview toggle uses native <details> with animated open/close
- Arrow indicators on right side (hide preview ▲ / show preview ▼)
- No-JS fallback preserved (links navigate to dedicated pages)
- CSS grid animation for smooth expand/collapse transitions
- Fade-in animation for namespace dropdown
- Auto-focus textarea on details open (progressive enhancement)
- Falls back gracefully if browser lacks support