This will make custom styles for PbNation. It can create styles in the form of Greasemonkey scripts, Firefox extensions, and as CSS stylesheets.

To use the Greasemonkey script, you need Firefox and Greasemonkey.
To use the Firefox extension, you just need Firefox.
To use the stylesheet, you're on your own. I think Opera and Safari have options to use them. I dunno, try searching for it.

To create your own style, go to creator.
To view and download previously made styles, go to the showcase