Update padding for better visual consistency

**Old:**
![screenshot 2014-08-12 10 40 52](https://cloud.githubusercontent.com/assets/2002702/3885010/814e3cce-21b9-11e4-9e7e-579063095717.png)

**New:**
![screenshot 2014-08-12 10 40 42](https://cloud.githubusercontent.com/assets/2002702/3885011/8357541a-21b9-11e4-822c-df64c71b7c6c.png)

Don't quote numbers, it's unpredictable in Sass.