Adaptive Tab Bar Colour changes the Firefox theme color to match the appearance of the current website.
Open source
20 alternativesFirefox CSS Hacks
Firefox CSS Hacks collects user stylesheets for changing the appearance of Mozilla Firefox.
About Firefox CSS Hacks
Firefox CSS Hacks is a GitHub repository of CSS stylesheets that change how Mozilla Firefox looks. The styles are mostly self-contained and can be mixed with each other somewhat freely. Setup means enabling a preference in about:config and creating userChrome.css and userContent.css files in your Firefox profile. The repository says its styles are tested only on Windows 10 and, to a lesser extent, on Linux.
Pricing is not clearly stated.
Key features
- Self-contained CSS stylesheets for Firefox appearance changes
- Manual and git-based setup instructions
- Style dependencies noted at the top of dependent files
- MPL-2.0 licensed repository
Watch out for
- No promises about compatibility with third-party styles
- Possible wrong behavior with native widgets such as titlebars and window control buttons
Firefox CSS Hacks at a glance
- Category
- Software & Utilities › Firefox Extensions
- Type
- Open-source project
- Pricing
- Not confirmed. Check the site
- Platforms
- Linux, Windows
- Details verified
- Oct 22, 2026 · Official source
- Open source
- Yes · Source code
- Language
- English
- Last checked
- Oct 5, 2026 · Online when checked
- Listed
- Oct 5, 2026
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Firefox CSS Hacks FAQ
Can I keep my own rules when I update?
Yes, if you install with git. The README says git pull will not replace your userChrome.css file, so your own rules there are kept.
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