userChrome.css

:root {
  --sidebar-min-width: 136px;
  --sidebar-visible-width: 162px;
  --uc-window-control-width: 898px; /* Space reserved for window controls */
  --uc-window-drag-space-width: 0px; /* Extra space reserved on both sides of the nav-bar to be able to drag the window */
  --uc-toolbar-height: 32px;
}

#sidebar-header {
  overflow: hidden !important;
}

#tabbrowser-tabs {
  visibility: collapse !important;
}

#sidebar-box #sidebar-header {
  display: none !important;
}

#sidebar,
#sidebar-header {
  position: relative !important;
  min-width: var(--sidebar-min-width) !important;
  max-width: var(--sidebar-min-width) !important;
transition: .1s ease .1s;
  z-index:1;
}

#sidebar-box:hover :-moz-any(#sidebar,#sidebar-header) {
  background-color: var(--toolbar-bgcolor) !important;
  min-width: var(--sidebar-visible-width) !important;
  max-width: var(--sidebar-visible-width) !important;
  margin-right: calc((var(--sidebar-visible-width) - var(--sidebar-min-width)) * -1) !important;
  z-index:1;
  position: relative !important;
transition: .21s ease 3.20s;

}


#nav-bar::before,
#nav-bar::after{
  content: "";
  display: -moz-box;
  width: var(--uc-window-drag-space-width);
}

toolbar#nav-bar::after{ width: calc(var(--uc-window-control-width) + var(--uc-window-drag-space-width,0px)) }

:root:not([uidensity="compact"]){--uc-toolbar-height: 38px}

#TabsToolbar{ visibility: collapse !important }

:root:not([inFullscreen]) #nav-bar{
  margin-top: calc(0px - var(--uc-toolbar-height));
}

#toolbar-menubar{
  min-height:unset !important;
  height:var(--uc-toolbar-height) !important;
  position: relative;
}















menupopup {
	-moz-appearance: none !important;
	padding: 8px 2px 8px 2px !important;
	background-color: #2B2B2B !important;
	border: 1px #A0A0A0 solid !important;
	min-width: 280px !important;
}
menuseparator {
	-moz-appearance: none !important;
	border: none !important;
	padding: .5px 0px .5px 0px !important;
	margin: 4px 8px 4px 8px !important;
	background-color: #808080 !important;
}
menuitem, menu {
	-moz-appearance: none !important;
	color: white !important;
	padding: 7.5px 0px 7.5px 0px !important;
}
menuitem[disabled="true"], menuitem[disabled="true"] > .menu-text {
	color: gray !important;
}
menuitem:hover, menu:hover, menu[open="true"], menuitem[_moz-menuactive="true"]	 {
	-moz-appearance: none !important;
	padding: 7.5px 0px 7.5px 0px !important;
	background-color: #414141 !important;
}
menugroup {
	padding: 0px !important;
	background-color: transparent !important;
}
menuitem > .menu-text, menuitem > .menu-iconic-text {
	color: white !important;
}
menuitem[type="checkbox"] {
	padding-left: 8px !important;
	padding-top: 6.5px !important;
	padding-bottom: 6.5px !important;
}
menuitem[type="radio"] {
	padding-left: 8px !important;
	padding-top: 6.5px !important;
	padding-bottom: 6.5px !important;
}
menuitem[type="checkbox"] > .menu-iconic-text, menuitem[type="radio"] > .menu-iconic-text {
	padding-left: 5px !important;
}
menuitem[checked="true"][type="checkbox"] > .menu-iconic-left {
	padding: 7px 0px 0px 0px !important;
	border: solid white;
	border-width: 0 0 2px 2px;
	transform: rotate(-45deg) scale(.75);
	margin-bottom: 4px !important;
}
menuitem[checked="true"][type="radio"] > .menu-iconic-left {
	padding: 1px !important;
	border: solid white;
	height: 17px !important;
	border-radius: 100%;
	background: white;
	transform: scale(.5);
}
menucaption {
	background-color: transparent !important;
	color: white !important;
}
#ContentSelectDropdown > menupopup {
	background-image: none !important;
}
#ContentSelectDropdown {
	padding: 0px !important;
}
menulist {
	-moz-appearance: none !important;
	padding: 4px 4px 4px 4px !important;
	border: 2px solid #666666 !important;
	background-color: transparent !important;
}
menulist:hover {
	padding: 4px 4px 4px 4px !important;
	border: 2px solid #999999 !important;
	background-color: transparent !important;
}
menulist[open="true"]  {
	border: 2px solid #666666 !important;
	background-color: #333333 !important;
}
#context-back > .menu-iconic-left, #context-forward > .menu-iconic-left, #context-reload > .menu-iconic-left, #context-stop > .menu-iconic-left, #context-bookmarkpage > .menu-iconic-left {
	padding: 0px !important;
}
.menu-iconic-left {
	-moz-appearance: none !important;
	padding: 0px 5px 0px 9px !important;
}
.menu-right {
	-moz-appearance: none !important;
	padding: 7.5px !important;
	margin-right: 6px !important;
	color: white !important;
	border: solid white;
	border-width: 0 2px 2px 0px;
	transform: rotate(-45deg) scale(.55);
}
tooltip {
	-moz-appearance: none !important;
	color: white !important;
	background-color: #2B2B2B !important;
	border: 1px solid #767676 !important;
	padding: 6.5px !important;
}



#TabsToolbar
{
opacity: .2 !important;
}