Installation

• install this theme mozilla addons.
• Set your firefox appearence to dark in settings/general
• Navigate to about:support and find 'Profile folder' and click 'open folder'.
• Navigate to about:config and set toolkit.legacyUserProfileCustomizations.stylesheets to 'true'.
• create a folder inside the opened folder named 'chrome'.
• move userChrome.css and userContent.css into the folder you just created.
• close and reopen firefox.
• Update firefox to the latest version for the best experience