Installation

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 and set it 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. Copy the chrome folder into your profile and restart¹ Firefox.
5. Customise everything to your liking. (optional)

^{1) If you're running into trouble with a restart seemingly not working you can navigate to about:profiles and click the »Restart Normally«-Button.}

IMPORTANT

Attention Windows users

It seems like flexbox (within the Firefox UI) is inheritly broken on Windows. In order to fix the One-Line layout on windows please substitute the responsive include with the version for windows. This will ensure that the layout doesn't break but since it can't use flexbox the UI reordering does not work.