Update jquery-ui.custom.css

there was an "s" at the end. If you merge css files you will get a white screen.

Author: senders

Resources/Css/JQueryUi/jquery-ui.custom.css

@@ -430,4 +430,4 @@
     left: -4px; /*must have*/
     width: 200px; /*must have*/
     height: 200px; /*must have*/
-}s
+}