Update article layout

Turning up the font size slightly so it's easier to read. Also expanding the max-width slightly to maintain letters per length ratio. Also introducing a max-height to the table of contents. What do you think, should we do something more to friendlify it?

This also fixes a bug where when you clicked on links in the table of contents the page would scroll to the heading, but it would be placed underneath the header.

Closes #54 
updates #38