Jj log in style

![screeenshot](https://cloud.githubusercontent.com/assets/4236592/5399062/acc00940-815f-11e4-9a28-3c73080305f3.png)

Our import TypeKit only has bold, italic, bold-italic and regular. So in this case **600** is not a valid weight, it would be 700.
So to make this more generic i would suggest a Sass mixin for setting font style and font weight.
Discussed details in person.