Fixed up formatting of code and added a bit of responsiveness

Hey there!
I moved styles from internal to external file: Makes code cleaner and easier to maintain in the future.

Added responsive fix when the screen is below 900px, looks nice on mobile in my opinion and also on tablets.

Differences:

Before:
![](http://i.imgur.com/DFvQz20.png)

After:
![](http://i.imgur.com/lvgqIB4.png)


Before: 
![](http://i.imgur.com/ptYsPBa.png)

After: 
![](http://i.imgur.com/joG06yk.png)

:)