Highlight selectors start with "+"(adjacent sibling selector).

before:
![before](https://cloud.githubusercontent.com/assets/3435149/3812358/4fd92ff6-1ca9-11e4-8c13-ddd5a8d50ac9.png)

after:
![after](https://cloud.githubusercontent.com/assets/3435149/3812362/53ddf870-1ca9-11e4-92f9-be3a1363146a.png)