CSS Cleanup

- Comments are normalized across entire codebase (JavaDoc style)
- 4 space indentation (as the entire organization uses this convention)
- Some minor tweaks
 
To review changes without the whitespace: https://github.com/guardian/frontend/pull/1050/files?w=0

![CSS](http://img.pandawhale.com/post-18529-Yes-mlkshk-1nAi.gif)