This website is very well made. Snappy, nice design, good discoverability and information architecture.
There aren't many web (-designs) I really like. Most of them feel off in some way or another. Another good one would be MDN.
Does anyone with design competency know what it is I like about the design? Are there some known principles at hand here that I can learn more about?
Beyond that, it does have good fundamental design. Hierarchy of typography is simple and clear, they font used for the article copy is legible and sized nicely. And, because of he lack of advertisements and attempts to pull you further into the site, there's enough white space to give it a more relaxed feeling.
If you want to learn the fundamentals of design, pick up the Non-Designers Design Book. Quick read with great explanations of the core principles of good information design.
I found this amusing bio on the Amazon author's page:
Robin Williams spent twenty-five years writing computer and design books and was one of the top three best-selling computer book authors in the world. But the world changed and no one bought computer books anymore, so she went to London and formalized her long study of Shakespeare with an M.A. and Ph.D. in Shakespeare studies.