docs: utilize monome/docs css https://github.com/monome/docs

[jlmitch5]

with the open-sourcing of the monome docs (https://github.com/monome/docs), I think it'd be cool to use the css from there for the teletype web docs, to help eliminate drift, and also take advantage of some of the css tweaks people are discussing on lines (https://llllllll.co/t/docs-now-more-open/26149/3)

Probably best to wait a bit to see if there are any changes that arise out of the discussion before trying to take this one.