Unfucks Firefox beyond 89 (Proton) on Windows - updated for 141

userChrome.css

/* https://addons.mozilla.org/en-US/firefox/addon/windows-10-dimmed/ */

/* https://www.reddit.com/r/firefox/comments/1ftnlvn/firefox_v1310/lpth76q/ */
#alltabs-button {display: none !important;}

/* Revert tab throbber - for Nightly 57 as of 9/20/2017 */
.tab-throbber[busy]::before {
	/* https://www.reddit.com/r/FirefoxCSS/comments/1em6fzz/tab_loading_throbber_icons_removed_in_129/ */
	/* Download the PNG and place it in the same folder of useChrome.css */
	background-image: url('loading.png') !important;
	animation: unset !important;
}
.tab-throbber[busy]:not([progress])::before {
	/* Grays the blue during "Connecting" state */
	filter: grayscale(100%);
}
@media (min-resolution: 2dppx) {
	.tab-throbber[busy]::before {
		background-image: url('chrome://global/skin/icons/loading@2x.png') !important;
	}
}

/*** Tighten up drop-down/context/popup menu spacing (8 Sep 2021) ***/
menupopup:not(.in-menulist) > menuitem, 
menupopup:not(.in-menulist) > menu {
  padding-block: 4px !important; /* reduce to 3px, 2px, 1px or 0px as needed */ 
  min-height: unset !important; /* v92.0 - for padding below 4px */
}
:root {
  --arrowpanel-menuitem-padding: 4px 8px !important;
}

/* Not loaded yet (also visited) */
.tabbrowser-tab:not([selected="true"])[pending] .tab-label,
.tabbrowser-tab:not([selected="true"])[visited] .tab-label {
	font-style: italic !important;
}

/* 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;*/
	background: #d4d4d4 !important;
	color: #707070 !important;
}

/* TABS: height - https://www.tenforums.com/browsers-email/190334-latest-firefox-disaster-excessive-tab-height-post2367617.html#post2367617 */
:root {
 --tab-toolbar-navbar-overlap: 0px !important; /* fix for full screen mode */
 --tab-min-height: 30px !important;
}
:root #tabbrowser-tabs {
 --tab-min-height: 30px !important;
}
#TabsToolbar {height: var(--tab-min-height) !important;}