A comprehensive dark theme for Firefox
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🌚 FF Midnight - A Dark Theme for Firefox

FF Midnight is a comprehensive dark theme system for Mozilla Firefox. It features interface styling that goes beyond the default built-in dark theme of the browser.

FF Midnight styles the complete interface in a dark color scheme, including Sidebars, Preference pages, View source page, PDF Viewer, all Firefox About:Pages and it also features a dark theme for popular addons such as uBlock Origin and Multi-Account Containers.

🎨 Theme color options

FF Midnight has 3 different dark color schemes that you can choose from:

  • Cosmos - A dark blue theme (default)
  • Galaxy - A dark blue-gray theme
  • Redshift - A dark brown theme

More color schemes wil be added in the future.

Opinionated styles

Some styles and colors may not be optimal for accessibility but are based on personal preferences. For example the 'flat' urlbar style and custom Tab indicators for Container tabs (find the different options in tab-indicator.css).

🛠 Extension in development

An extension of FF Midnight is currently in development. The goal is to have FF Midnight hosted on addons.mozilla.org. That should make installing and updating easier and will allow for the different options to be configured in a preference panel. Until the extension is finished you can manually install the theme by following the instructions below. Stay tuned!

⚙️ Installation

As a prerequisite you should use the default Firefox dark theme. It can be selected on the about:addons#themes page. If you don't, parts of the interface may become unreadable after installation.

  1. Find your Profile folder (Profile folder names are different for everyone):
    Go to the URL about:support > Profile Folder > Show in Finder (MacOS) or Open folder (Windows).
    Alternatively go to about:profiles > Root Directory > Show in Finder (MacOS) or Open Folder (Windows).
  2. Copy the contents of this repository's theme folder to the chrome folder in your Profile folder. Create the chrome folder in your Profile folder if there is none yet.
  3. Optional: To change the default Cosmos color scheme to Galaxy or Redshift open userChrome.css and userContent.css and follow the instructions in there.
  4. Optional: If you have the uBlock Origin and/or Multi-Account Containers extensions installed you can add theme styling to their interfaces as well.
    Go to about:debugging#addons and find and copy the UUID of these addons. Open the CSS files for these addons located in theme\css\ff-midnight\extensions and paste the UUID in the correct location (Instructions found in the css file).
  5. Optional: Add a custom background image for the About:Home and About:Newtab pages: Open background-image.css and follow the instructions in there.
  6. Restart the browser.

🌌 Preview

FF Midnight screenshot

Preferences page, Sidebar, Custom background for About:Newtab, Custom Tab indicators, uBlock Origin and Multi-Account Containers panels

FF Midnight screenshot

View Source page, About:Addons page, Page Info dialog window

FF Midnight Cosmos palette FF Midnight Galaxy palette FF Midnight Redshift palette

👯‍♀️ Contributions

This theme is tested on MacOS but it should work fine on Windows and Linux. If you find any bugs or have suggestions all feedback is welcome.