Prevent overlap between global nav items and burger icon

Thanks to Patrick S. for reporting this.

### Before

![screen shot 2014-03-03 at 14 41 48](https://f.cloud.github.com/assets/85783/2310332/120bc4d6-a2e2-11e3-9097-26be2e1ca758.PNG)

### After

![screen shot 2014-03-03 at 14 42 03](https://f.cloud.github.com/assets/85783/2310335/189b28a0-a2e2-11e3-8280-38dbce4e09cf.PNG)

![ ](http://media1.giphy.com/media/jMTGp9G2zGFYQ/200.gif)