Thunderbird_91_ESR/css/general/menubar_below_tabs.css
/* Thunderbird userChrome.css tweaks ************************************************************/
/* Github: https://github.com/aris-t2/customcssfortb ********************************************/


#mail-toolbar-menubar2 {
  -moz-box-ordinal-group: 20 !important;
  -moz-window-dragging: unset !important;
  border: unset !important;
  padding-top: unset !important;
  margin-top: unset !important;
}

#messengerWindow[sizemode="normal"] #mail-toolbar-menubar2 {
  border-left: 1px solid rgba(0,0,0,.4) !important;
  border-right: 1px solid rgba(0,0,0,.4) !important;
}
		
@media (-moz-os-version: windows-vista), (-moz-os-version: windows-win7) {

	@media not all and (-moz-windows-glass) {

		#mail-toolbar-menubar2:not(:-moz-lwtheme) {
		  background: linear-gradient(rgba(255,255,255,.4), rgba(255,255,255,.4)),
					  linear-gradient(-moz-dialog, -moz-dialog) !important;
		}
		
		
		#mail-toolbar-menubar2[autohide="false"] + #tabs-toolbar > .titlebar-placeholder[type="caption-buttons"],
		#messengerWindow #tabs-toolbar #titlebar-placeholder-on-TabsToolbar-for-captions-buttons[type="caption-buttons"] {
		  display: -moz-box !important;
		}

		#messengerWindow[sizemode="maximized"] #tabs-toolbar {
		  margin-top: -1px !important;
		}
		@media all and (-moz-windows-theme: aero) {
			#mail-toolbar-menubar2:not(:-moz-lwtheme) {
			   background: #eaf2fb !important;
			}
			#mail-toolbar-menubar2 {
			  padding-bottom: 0px !important;
			  margin-bottom: 0px !important;
			}
		}
		@media all and (-moz-windows-classic) {
			
			#mail-toolbar-menubar2 menubar > menu {
			  appearance: none !important;
			}
			
			#mail-toolbar-menubar2:not(:-moz-lwtheme):not(:-moz-lwtheme-brighttext) toolbarbutton > :is(label,description),
			#mail-toolbar-menubar2:not(:-moz-lwtheme):not(:-moz-lwtheme-brighttext) menubar > menu:not([_moz-menuactive="true"]):not(:hover):not([open="true"]) {
			  color: black !important;
			}
			#mail-toolbar-menubar2:not(:-moz-lwtheme):not(:-moz-lwtheme-brighttext) menubar > menu[_moz-menuactive="true"] {
			  color: white !important;
			}
			#mail-toolbar-menubar2:-moz-lwtheme {
			  appearance: none !important;
			  background: linear-gradient(rgba(255,255,255,.4), rgba(255,255,255,.4)) !important;
			}
			
			#messengerWindow:not([sizemode="maximized"]) #tabs-toolbar {
			  margin-top: 3px !important;
			}

		}
	}

}

/*move menubar below tabs for Windows XP, Linux*/
@media not all and (-moz-os-version: windows-vista) {
@media not all and (-moz-os-version: windows-win7) {
@media not all and (-moz-os-version: windows-win8) {
@media not all and (-moz-os-version: windows-win10) {
	
	#mail-toolbar-menubar2 menubar > menu {
	  appearance: none !important;
	}
	
	#mail-toolbar-menubar2:not(:-moz-lwtheme):not(:-moz-lwtheme-brighttext) menubar > menu:not([_moz-menuactive="true"]):not(:hover):not([open="true"]) {
	  color: black !important;
	}
	
	#mail-toolbar-menubar2 {
	  -moz-box-ordinal-group: 20 !important;
	  -moz-window-dragging: unset !important;
	  border: unset !important;
	  padding-top: unset !important;
	  margin-top: unset !important;
	}
	
	#mail-toolbar-menubar2[autohide="false"] + #tabs-toolbar > .titlebar-placeholder[type="caption-buttons"],
	#messengerWindow #tabs-toolbar #titlebar-placeholder-on-TabsToolbar-for-captions-buttons[type="caption-buttons"] {
	  display: -moz-box !important;
	}

	#messengerWindow[sizemode="maximized"] #tabs-toolbar {
	  margin-top: -1px !important;
	}

	#mail-toolbar-menubar2:-moz-lwtheme {
	  appearance: none !important;
	  background: linear-gradient(rgba(255,255,255,.4), rgba(255,255,255,.4)) !important;
	}
	
	#mail-toolbar-menubar2:not(:-moz-lwtheme) {
	  appearance: none !important;
	  background: linear-gradient(rgba(255,255,255,.4), rgba(255,255,255,.4)),
				  linear-gradient(-moz-dialog, -moz-dialog) !important;
	}
	
	@media all and (-moz-windows-classic) {
		
		#messengerWindow:not([sizemode="maximized"]) #tabs-toolbar {
		  margin-top: 3px !important;
		}

	}

}}}}

@media (-moz-os-version:windows-win8),(-moz-os-version:windows-win10) {
	#mail-toolbar-menubar2 {
	  appearance: none !important;
	  -moz-box-ordinal-group: 20 !important;
	  -moz-window-dragging: unset !important;
	  border: unset !important;
	  padding-top: unset !important;
	  margin-top: unset !important;
	}
	
	#mail-menubar:not(:-moz-lwtheme) > menu {
	  color: black !important;
	}

	#mail-toolbar-menubar2[autohide="false"] + #tabs-toolbar > .titlebar-placeholder[type="caption-buttons"],
	#messengerWindow #tabs-toolbar #titlebar-placeholder-on-TabsToolbar-for-captions-buttons[type="caption-buttons"] {
	  display: -moz-box !important;
	}

	@media all and (-moz-windows-theme: aero) {
		#mail-toolbar-menubar2 {
		  padding-bottom: 0px !important;
		  margin-bottom: 0px !important;
		}
	}
	
	#messengerWindow:-moz-lwtheme #mail-toolbar-menubar2 {
	  background-color: var(--toolbar-bgcolor) !important;
	}
}


@media (-moz-os-version:windows-win8) {
	
	#mail-bar3:not(:-moz-lwtheme),
	#messengerWindow #navigation-toolbox #mail-toolbar-menubar2:not(:-moz-lwtheme) {
	  appearance: none !important;
	  background: #f9f9fa !important;
	}

}

@media (-moz-os-version:windows-win10) {
	
	#mail-bar3:not(:-moz-lwtheme),
	#messengerWindow #navigation-toolbox #mail-toolbar-menubar2:not(:-moz-lwtheme) {
	  appearance: none !important;
	  background: #f0f0f0 !important;
	}
	
	#messengerWindow[sizemode="normal"] #mail-toolbar-menubar2 {
	  border-left: 0 !important;
	  border-right: 0 !important;
	}

}
