New API entertainment site

About a week or so ago I transformed clownsareawesome.com site into the API entertainment site. I spent a couple hours putting it all together and was fairly happy with the result. I am a little disappointed in the look of the menu graphics but figured I could smooth those as time went on.

I happened to be looking around the web, like ya do, and came across this article on alistapart.com on making sprite like menus in CSS. I figured I would go for it. I started trying to mimic their example and finally got fed up with trying to recreate this, so I just created my own. Unfortunately it doesn’t seem to work in Mozilla or IE7, I don’t know what I did wrong since the example on alistapart works fine in all browsers.

Basically, I need help. I can figure it out. Here is a mockup of the new API site that works in IE6, that I would like to get to work across most if not all platforms. If you have any idea on what I need to do or even just something you think I should try, let me know. Here and Here are the CSS files.

Do I need to combine those or is it because my menu is in a DIV instead of just on a page? Basically I am at the limit of my CSS knowledge and want to get this figured out.

Thanks in advance for any and all help.