Darker text for better contrast - fixes #37

I think @torbjoernk has a fair point in #37 saying that the text contrast could be better. This pull darkens the body text a bit.

Before:
![screen shot 2013-07-16 at 2 18 58 pm](https://f.cloud.github.com/assets/6104/806954/4f859622-ee45-11e2-8b8e-c3275fcbb58d.png)

After:
![screen shot 2013-07-16 at 2 18 49 pm](https://f.cloud.github.com/assets/6104/806956/54795128-ee45-11e2-9865-f90717f9c350.png)