Hm, it’s working fine in all my Mac browsers. As an aside, I wouldn’t recommend making a page so heavily reliant of JavaScript, though. With JS off, almost nothing on the page shows up. JavaScript can work nicely to enhance a page, but it’s not a good idea for the page to be dependent on it.
I realize this doesn’t address your problem, though. I presume you are viewing this on Windows?
EDIT:
Maybe you could just try putting this directly in the CSS:
Regarding the overuse of JS in a web page, it doesn’t seem to be a problem in my opinion since if you disable java script most pages won’t work anyway.