Using active/inactive system colors in Firefox

After the horrible Proton UI in Firefox v89, there was no difference between active/inactive window colors. The theme would simply remain static while you switched to other windows, which from the usability point of view, is absurd.

After digging a bit, I found an userChrome.css hack to use the system colors on Firefox window. As of Firefox 98, it appears to work well:

/* Show active colors on main menu bar */
/* https://superuser.com/a/1675508 */
#TabsToolbar,
#navigator-toolbox {
	background: -moz-accent-color !important;
	color: white;
}
#TabsToolbar:-moz-window-inactive,
#navigator-toolbox:-moz-window-inactive {
	background: unset !important;
	color: unset;
}

Just for the record: this is how you activate userChrome.css stuff.