Set as Homepage:
1. Save this HTML file locally
2. Open Firefox → Settings → Home
3. Set "Homepage and new windows" to Custom URLs
4. Paste the file path: file:///path/to/index.html

Works with: Firefox, Zen Browser, Waterfox, LibreWolf, Floorp, and all Firefox forks.

No internet required! All assets are inline. Settings are saved to your browser's localStorage.