Fix margin around the content card squares to improve readability

![screen shot 2014-10-17 at 1 47 17 pm](https://cloud.githubusercontent.com/assets/633012/4685889/49d2d60a-563f-11e4-9524-b72d5220c912.png)
![screen shot 2014-10-17 at 1 49 32 pm](https://cloud.githubusercontent.com/assets/633012/4685891/49ee830a-563f-11e4-8b72-e132d349cb99.png)
![screen shot 2014-10-17 at 1 50 15 pm](https://cloud.githubusercontent.com/assets/633012/4685890/49ec504e-563f-11e4-80b2-866070693fb0.png)