User blog comment:BertH/Fluid layout is arriving on December 4/@comment-1192804-20131204134019/@comment-452-20131204222702

As Penguin-Pal said, you need to add !important, here: background-image: url("http://static4.wikia.nocookie.net/silent/images/e/e9/CherylWall.jpg") !important;

edit: also, to basically every background-related line, like: background-position: top center !important; (You currently have top and center on two lines, which doesn't work.)