Brief - feed reading extension for Firefox

I don't much like the look of the brief "side-bar."  I'd really prefer something all-html (not unlike the layout of these forums, actually, this would look great as my feed-reading page...)  Basically I'm wondering whether it's possible to change the look and feel of brief by modifying the style of the "side-bar" and "top-bar."  I just don't like the way they stand out, and I wanna get rid of them (well... modify the top-bar and remove the sidebar.)  I can't get rid of the side-bar, though, because there's no way to view older feeds without using the side-bar.