If you're viewing that website on a desktop, I strongly suggest removing max-width: 90ch from the body css. Instead of 50% white space, it goes full width and makes the table substantially more readable (particularly the code samples).
Hilariously enough I was initially confused by this comment because the webpage rendered so readably for me - the base CSS is actually quite reasonable and because I have JS disabled by default the page never re-rendered into the thinner mode.
It may be my specific setup. But on a 1440p display, 125% OS scale, I'm seeing more white left/right than actual content in the middle. It is also wrapping the code making it difficult to read.
