Apply CSS to the correct config.styleableChrome window.

xulmus/content/config.js

@@ -47,7 +47,7 @@ const config = { //{{{
     get mainWindowID() "mainplayer",
     get visualbellWindow() document.getElementById(this.mainWindowID),
 
-    styleableChrome: "chrome://songbird/content/xul/layoutBaseOverlay.xul",
+    styleableChrome: "chrome://gonzo/content/xul/mainplayer.xul",
 
     autocommands: [["BookmarkAdd",        "Triggered after a page is bookmarked"],
                    ["ColorScheme",        "Triggered after a color scheme has been loaded"],