userChrome.css

#nav-bar {
  height: 40px;
  flex-direction: row-reverse;
}

#nav-bar-overflow-button {
  display: none;
}

hbox#nav-bar-customization-target {
  margin-top: 3px !important;
}

#PanelUI-menu-button {
  margin-top: 6px;
}

#urlbar {
  --urlbar-height: 32px !important;
  --urlbar-toolbar-height: 32px !important;
}

#back-button,
#forward-button,
#stop-reload-button {
  display: none;
}

#downloads-button,
#unified-extensions-button {
  margin-top: -4px !important;
}

#navigator-toolbox {
  width: 100vw !important;
  position: absolute !important;
  z-index: 9001 !important;
  top: -40px;
}

#urlbar-container {
  pointer-events: none;
  position: absolute;
  top: -1000px;
}

#PanelUI-menu-button {
  padding-right: 0 !important;
}

#sidebar-splitter {
  width: 37px !important;
  z-index: -10 !important;
}

toolbar#TabsToolbar {
  display: none;
}

#sidebar-box {
  position: absolute !important;
  height: 100%;
  width: 435px !important;
  z-index: 1;
  margin-top: 40px !important;
}

#sidebar-box #sidebar {
  width: 435px !important;
}

#appcontent {
  z-index: 3;
}

#sidebar-header {
  display: none;
}

#tabbrowser-tabbox {
  z-index: 1 !important;
}

:root:hover:not(:has(#tabbrowser-tabbox:hover)),
:root:not(:has(#toolbar-menubar[inactive])),
:root:has(#navigator-toolbox:focus-within) {
  #navigator-toolbox {
    top: auto;
  }

  #sidebar-box {
    z-index: 8 !important;
  }

  #urlbar-container {
    pointer-events: all;
    position: inherit;
  }
}