This is seriously awful.

He's using some kind of condensed serif at an enormous size that makes it very uncomfortable for screen reading. His list numbers are illegible, misaligned, and extremely far away from the list items. He sprinkles SMALL CAPS everywhere FOR SOME REASON. The contents page is particularly bad, using a Futura-esque font against a serif at the same size, with bizarre spacing, failing to make a hierarchy or pleasing design.

There are many great design documents. This is not one of them. If you want to improve your design skills, do yourself a favor and avoid this charlatan.