Update player.css

Fixes code-charity#2567

js&css/extension/www.youtube.com/appearance/player/player.css

@@ -112,7 +112,7 @@ html[it-player-color]:not([it-player-color='red']):not([it-player-color='normal'
 html[it-player-color]:not([it-player-color='red']):not([it-player-color='normal']) .ytp-scrubber-button,
 html[it-player-color]:not([it-player-color='red']):not([it-player-color='normal']) .ytp-menuitem[aria-checked='true'] .ytp-menuitem-toggle-checkbox,
 html[it-player-color]:not([it-player-color='red']):not([it-player-color='normal']) .ytp-settings-button.ytp-hd-quality-badge:after {
-	background-color: var(--it-player-color) !important;
+	background: var(--it-player-color) !important;
 }
 
 html[it-player-color]:not([it-player-color='red']):not([it-player-color='normal']) .ytp-swatch-color {