I'd be willing to write said CSS.
That Firefox addon I linked yesterday lets you override the CSS. Are you still willing to do this, or should I give it a go? I played with it a bit yesterday and it's pretty easy to make the site look less conspicuous, but it'll be pretty hard to make it look like a damn spreadsheet without crippling usability. Also, I'm not sure what to do about the ads... It's easy to hide them, but it's not fair to Chicken. Thoughts?