It wasn't the timestamp that fixed it. The timestamp isn't really needed, to be honest; it was just a way for me to see if my current version of code was actually in cache (if the timestamp updated, I knew the cache was current). With Wikia's current system of JS testing, you always get the latest copy, so we probably can just get rid of it.
The problem actually appeared to be a typo in the CSS, which I fixed. One missing apostrophe. :)