- Dark/light preview theme toggle with localStorage persistence and
dark CSS injection in preview, export, and embed
- External CSS/JS resources modal with per-fiddle persistence in
options column, injected as link/script tags
- Keyboard shortcuts cheat sheet modal (? button or ? key)
- Mobile-responsive CSS with breakpoints at 768px and 480px
for both editor and browse pages
- Browse dashboard at / with search, framework filter, tag pills, and pagination
- Tags system with autocomplete datalist and per-fiddle tag management
- Listed/unlisted toggle for visibility control (unlisted still accessible via direct URL)
- Export standalone HTML with inlined CSS/JS and framework CDN tags
- QR code modal for sharing fiddle URLs
- Embed mode at /embed/:id for minimal preview-only rendering
- Extract shared loadScript() utility from 4 files into utils.js
- Database schema: listed column, tags and fiddle_tags tables with index
