Note: Download your desired CSS file from this repo and rename it as `userChrome.css` (important). ## How to use a userChrome.css theme 1. Type `about:config` into your URL bar. Click on the **I accept the risk** button if you're shown a warning. 2. Seach for **`toolkit.legacyUserProfileCustomizations.stylesheets`**, **`layers.acceleration.force-enabled`**, **`gfx.webrender.all`** and **`svg.context-properties.content.enabled`** and set them to **`true`**. 3. Go to your profile folder: - Linux: `$HOME/.mozilla/firefox/######.default-release/` - MacOS: `Users/[USERNAME]/Library/Application Support/Firefox/Profiles/######.default-release` - Windows: `C:\Users\[USERNAME]\AppData\Roaming\Mozilla\Firefox\Profiles\######.default-release` 4. If it doesn't exist already create a folder called `chrome`. 5. Copy your desired `userChrome.css` into that folder. 6. *optional* Customise everything to your liking. _This guide is borrowed from Cascade repo. Credits: [github.com/andreasgrafen/cascade](https://github.com/andreasgrafen/cascade/blob/main/README.md#how-to-use-a-userchromecss-theme)_