Set margin of overlay to padding of element

I ran into an issue where I was using a large padding and the overlay was not covering exactly what I wanted. So by setting the margin of the overlay to the elements padding it fixed the issue.

![screen shot 2014-11-12 at 9 54 34 am](https://cloud.githubusercontent.com/assets/483829/5012170/fcaa5944-6a51-11e4-8134-f0c1437d0d1b.png)