Replacing links on home page with buttons

Turning the links below the explanatory paragraphs on the home page into white-on-blue buttons.
![screen shot 2013-09-13 at 8 44 08 pm](https://f.cloud.github.com/assets/911566/1142550/9aa5669a-1cd6-11e3-8b09-db5b2c2c634c.png)