- Go to
about:config
- Click on „Accept the Risk and Continue”
- Doubleclick on
toolkit.legacyUserProfileCustomizations.stylesheets
if it isn't already enabled
- Go to
about:profiles
- Find your profile -- ( „This is the profile in use and it cannot be deleted.” )
- Open the profiles root directory
- Create a folder called
chrome
- Copy the preferred
userChrome.css
anduserContent.css
there
- Click on the X button
- Doubleclick on the firefox icon
Windows style titlebar buttons
Macos style titlebar buttons