Try Bar finished; start on Docs Nav

A sticky navigation document tree for the documentation is really
shittily put together, but it's there. It responds (with intention) to
a scroll depth of more than 620px (i.e.: sticks when the user goes to
scroll past it).

Also a feeble attempt to get dynamic font-sizes for <pre> elements.
Doesn't work super well. I'm not even sure it should be an implemeneted
featue. Hard to say without actual content in the elements.