Edited CSS to work on Firefox, added one line reigning in max-width

The original bootstrap file would cause the screen to look like this
![ll](https://cloud.githubusercontent.com/assets/5894247/3862752/46f32a70-1f3f-11e4-9895-184bf39d08ae.png)
 in Firefox. I added `max-width: 100%;` to `[class*=span]` and it fixed the problem.