Fixes highlight styles

![screen shot 2014-05-10 at 7 39 27 pm](https://cloud.githubusercontent.com/assets/436680/2935945/bdcbcf56-d838-11e3-96b6-f5bb9f3d804a.png)

There is a little space before the first line of code within `.highlight` (see image above), this is because the `code` has a 5px left padding, so let's the `.highlight code` displays as `inline-block`.