Waterfox, Floorp, GNU IceCat & Ghostery

ONLY WORKS ON WATERFOX, FLOORP, GNU ICECAT & GHOSTERY

Remember to change your theme to anything other than "System theme - auto".
^ It's fine on Ghostery.

On Floorp, open Settings -> Look and Feel -> Browser appeareance and you need to select "Firefox Proton UI" or "Floorp Fluerial UI (deprecated), because "Firefox Photon・Lepton UI" and "GNOME Theme (deprecated)" doesn't work properly.

Firefox & LibreWolf

ONLY WORKS ON FIREFOX & LIBREWOLF

Remember to change your theme to anything other than "System theme - auto".