Fix sidebar issue

Prevent the sidebar from overlapping content.

This is how it looks without the style change:
![screen shot 2014-02-23 at 10 12 01 pm](https://f.cloud.github.com/assets/1172331/2243026/043e7a64-9d1b-11e3-86bf-9096adba05eb.png)

And this is what it looks like with the style change:
![screen shot 2014-02-23 at 10 11 48 pm](https://f.cloud.github.com/assets/1172331/2243028/14efeec4-9d1b-11e3-8ba7-89a23a14c93b.png)