this is not something you want to “override”, but instead you’ll want to use plain ol’ simple CSS to stylize this to match other styles on your site.
If you’re new to CSS, I’d recommend downloading firebug to help you figure out what is being stylized and w3school for learning.
I’m finding myself having the same problem. I just downloaded a fresh version of WP 3.5.1 and replaced my hosted sites “wp-admin” and “wp-includes” and it’s still not working. I also tried using the old browser upload vs. multiFile uploader and still no luck.
@bemsser– did you ever figure it out?
