Make the buttons page slightly more readable

The nice white lines aren't part of the design. I think this makes it a bit neater. Any objections?

![image](https://cloud.githubusercontent.com/assets/814861/5217441/5264b7fc-7638-11e4-83b4-8a43fa3aadee.png)
![image](https://cloud.githubusercontent.com/assets/814861/5217447/5d8ba564-7638-11e4-9e25-ee9917a48e41.png)
![image](https://cloud.githubusercontent.com/assets/814861/5217448/657ef1e0-7638-11e4-9e0b-cfbb0d786056.png)
![image](https://cloud.githubusercontent.com/assets/814861/5217452/6b62ba74-7638-11e4-977b-6a2736dbac80.png)