/* Installation * 1. Visit about:profiles and click your default profile's Root Directory's "Open Directory" button. * 2. Create the chrome/ folder if it doesn't exist. * 3. Save this file into that folder and edit it to your liking. * 4. Enable toolkit stylesheets by visiting about:config and setting toolkit.legacyUserProfileCustomizations.stylesheets to true. Just search for "toolkit.legacy" and double click it to make it true. * 5. Restart Firefox to apply changes. * See for more info: https://developer.mozilla.org/en-US/docs/Web/CSS/@document */ @-moz-document domain("archlinux.org"), domain("wikipedia.org"), domain("medium.com"), domain("freedesktop.org") { html {filter: brightness(50%) !important;} } /* Websites with iframes or frames must use CSS selectors that target just one element, otherwise, the CSS applies equally to the elements within them and causes the filter to stack. */ @-moz-document domain("mail.google.com") { html.aAX {filter: brightness(50%) !important;} }