On mobile, Firefox for Android has an neat addon for that: Dark Background and Light Text by Mikhail Khvoinitsky https://addons.mozilla.org/en-GB/android/addon

On mobile, Firefox for Android has an neat addon for that: Dark Background and Light Text by Mikhail Khvoinitsky https://addons.mozilla.org/en-GB/android/addon/dark-background-light-text/ https://addons.mozilla.org/en-GB/android/addon/dark-backgrou... It just works™ about everywhere. It is also available on the desktop version, although I've never tried it myself.