Seems silly to me to use a JS file, a file named "app.js" at that, for styling a page. Also, it steps on any custom styling as it renders outcome AFTER CSS has been loaded.
This file does two things, only:
Set background image from what looks like an attempt to use image tags to preload resources, to the "backgroundImage" property of:
1) body
2) #logo's parent element.
// And, that's silly. And, it steps on CSS, which should be controlling the view. Meh.