Fix margin around the content card squares to improve readability

before, the width  on mobile was escaping over the outside of the visible screen. also the green icon was too close to the above paragraphs

mobile & tablet
![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)