Adding a Background Color

I looked through the CSS but haven’t been able to fix this on my own. Is there a way I can add a background color to the Digg Digg buttons in the normal display mode? I don’t want the same white background as the rest of my theme but would rather have them contrast slightly.

Here’s an example of what I want to do. See how BuzzFeed’s social media buttons have a light blue background?
http://www.buzzfeed.com/louispeitzman/signs-youre-the-milhouse

Setting them off slightly from the main content with color makes the page look more organized and improves usability.

http://ww.wp.xz.cn/plugins/digg-digg/