Adapt css for mobile page

# Before

![Pantallazo_before](https://f.cloud.github.com/assets/1108789/121233/d8c063ee-6d81-11e2-9603-14d0e53330d0.png)

# After

![Pantallazo_after](https://f.cloud.github.com/assets/1108789/121235/e71a883e-6d81-11e2-8c96-5a089e6cf9fa.png)