FastDark by Shaban

FastDark is a lightweight dark mode for Firefox. It darkens websites with a single CSS filter instead of rewriting each page's colors, to avoid a white flash. Toggle it per site, keep images and videos normal, and it collects no data.

FEATURES
- Dark mode on every site, applied as soon as the page starts loading
- Images, videos and most embedded players keep their original colors
- Per-site on/off switch in the toolbar popup
- Keyboard shortcut: Alt+Shift+D toggles the current site (changeable in Firefox's Manage Extension Shortcuts)
- Skips pages that are already dark, using a best-effort check, so they aren't flipped back to light
- Choose your toolbar icon from four presets, or upload your own image
- Does not run on popular AI chatbot sites (ChatGPT, Claude, Gemini, Copilot, Le Chat, HuggingChat), which have their own dark themes

HOW IT WORKS
FastDark inverts the page with a CSS filter that the browser handles on the graphics side, then flips images and video back so they look normal. It runs no background timers and doesn't watch the page for changes after loading.

PRIVACY
FastDark collects and transmits no data. Your list of disabled sites and your icon choice are stored locally in your browser and never leave it.

KNOWN LIMITATIONS
- Colors are an approximation of a true dark theme, so some sites will look better than others
- Dark logos on transparent backgrounds can be hard to see on dark pages
- Images inside some web components, and background images defined in stylesheets hosted on other domains, may still appear inverted
- Dark-page detection runs once while the page loads, so a site that switches to dark later may briefly look wrong

If a site looks wrong, turn FastDark off for it using the toolbar popup or the shortcut.