Commercial: styling for article advertisement feature

Currently just changing body text to `textSans` - debate to be had around whether we want to include another font (`displaySans`) for the headlines

![screen shot 2014-04-28 at 17 15 20](https://cloud.githubusercontent.com/assets/74132/2819612/6e7a6eb8-cef0-11e3-9c72-51b8b94def16.png)