Style updates

Hi @seanbarclay, I've applied your CSS updates. Thanks! 

Couple of things:
- I added the @red bg for the Query Options header option, but had to pad it a bit.
- can I add the same bg for API Url as well? 
we usually write classes all downcase and with a `-` if we want to delimit them. if the class is needed for js, we prefix them with `js-`, like `js-my-class`