[OBSOLETE stopped working with firefox 71]
- Open about:config and set toolkit.legacyUserProfileCustomizations.stylesheets to true.
- Open a new tab on about:support
- Click the button next to “Profile Folder”
- Go to the “chrome” directory at the profile folder, or create it if it doesn’t exist.
- Create a file named “userChrome.css” (if it doesn’t exist) and open it in a text editor.
- Copy the css code from github.com/andreicristianpetcu/UserChrome-Tweaks
(copy of the css is at the bottom of this post) - Paste it into userChrome.css and save.
- Restart Firefox
userChrome.css
/*
* Makes tabs only 22px high rather than the default 29px
* Only works on compact mode, otherwise tab height will be normal
*/
[uidensity="compact"]:root {
--tab-min-height: 22px !important;
--newtab-margin: -3px 0 -3px -3px !important;
}
.tabbrowser-tab {
max-height: var(--tab-min-height) !important;
}
.tabs-newtab-button{
margin: var(--newtab-margin) !important;
}