increase margin size of problem description for beauty.

Before:
![27c04db2-aebe-476c-adce-1e7e2623da33](https://cloud.githubusercontent.com/assets/5453070/2808793/8af87450-cd46-11e3-9e8f-54cf94da9753.png)
 
After:
![4ca16f3c-6045-4b80-89fb-8940944dbecf](https://cloud.githubusercontent.com/assets/5453070/2808792/717ef198-cd46-11e3-9e7b-8eb6cdd5dcb4.png)