{...}: {
  programs.firefox = {
    enable = true;
    profiles = {
      laurent = {
        isDefault = true;
        settings = {
          "browser.startup.page" = 3; # always restore tabs
          "privacy.donottrackheader.enabled" = true;
          "browser.ctrlTab.sortByRecentlyUsed" = true; # change Ctrl+Tab behaviour
          "general.autoScroll" = true;
          # enable vertical tabs
          "sidebar.revamp" = true;
          "sidebar.verticalTabs" = true;
          "sidebar.visibility" = "hide-sidebar";
          # enable userChrome.css
          "toolkit.legacyUserProfileCustomizations.stylesheets" = true;
        };
        userChrome = ''
          #titlebar {
            display: none !important;
          }
        '';
      };
    };
  };
}