Better account page style/default background colour

I added in CSS rules to format the definition list used in the `/users/<name>` view, as well as declaring a background colour for the body, since I've noticed a few mentioning those minor stylistic issues.

Screenshot of the changes to the style, staged in Chrome:
![Screen Shot 2013-02-21 at 3 28 24 PM](https://f.cloud.github.com/assets/188480/181874/eabb6dca-7c5c-11e2-97f6-a00db33e65e3.png)