Update userChrome.css to comply with Firefox 89 UI

.mozilla/firefox/dotfiles.profile/chrome/userChrome.css

@@ -4,16 +4,9 @@
 		visibility: hidden !important;
 	}
 
-	/*  Move navigation bar up to fill tab bar space */
+	/* Remove titlebar */
-	#nav-bar {
+	#titlebar {
-		border-width: 1px !important;
+		display: none;
-		border-style: solid !important;
-		border-color: transparent !important;
-
-		margin-bottom: -1px !important;
-		margin-top: -29px !important;
-		margin-right: 0px !important;
-		margin-left: 0px !important;
 	}
 
 	/* Navigation bar color */