removing background gap on topic closures

This 
![screenshot 2014-02-26 17 33 06](https://f.cloud.github.com/assets/1681963/2276656/460a43d4-9f36-11e3-8410-96e1e27a26d8.png)

becomes 

![screenshot 2014-02-26 17 33 31](https://f.cloud.github.com/assets/1681963/2276658/4be9efca-9f36-11e3-8a0c-2aba45369b5a.png)