Firefox Customizations

Auto-hide Bookmarks Toolbar

~/.mozilla/firefox/<profile_dir>/chrome/userChrome.css

Block certain parts of a domain

~/.mozilla/firefox/<profile_dir>/chrome/userContent.css

@-moz-document domain(example.com) {
    div#header {
      background-image: none !important;
    }    
}

• ArchWiki page with useful tips