@namespace xul url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* Icons light/dark fix coloring hack filters */ :root { --gnome-convert-icon-to-symbolic-hack-filter: invert(100%) sepia(100%) grayscale(100%) brightness(200%) brightness(85%) invert(100%); } @media (prefers-color-scheme: dark) { :root { --gnome-convert-icon-to-symbolic-hack-filter: invert(100%) sepia(100%) grayscale(100%) brightness(200%) brightness(85%); } } /* OPTIONAL: Make all tab icons look kinda like symbolic icons */ @supports -moz-bool-pref("gnomeTheme.symbolicTabIcons") { tab .tab-icon-image { filter: var(--gnome-convert-icon-to-symbolic-hack-filter); } }