Random useful and not so useful hacks.

Fix your Firefox 1

  1. Browse to your Firefox profile directory.
  2. Create a folder named chrome.
  3. Create a file named userChrome.css and add the following: 
    .titlebar-color{
    color: -moz-accent-color-foreground;
    background-color: -moz-accent-color;
}
.tab-background{
    border-radius: 0px 0px !important;
    margin-bottom: 0px !important;
}
.tabbrowser-tab:not([selected=true]):not([multiselected=true]) .tab-background{
    background-color: color-mix(in srgb, currentColor 40%, transparent);
}
menupopup > menu, menupopup > menuitem{
    padding-block: 2px !important;
}
:root{
    --arrowpanel-menuitem-padding: 2px !important;
}
  4. Enter the about:config in the URL bar to open the config page.
  5. Filter to toolkit.legacyUserProfileCustomizations.stylesheets and set that option to true.
  6. Restart the browser.

See also: