It feels very easy to read. So much clutter has been taken away.
There’s nothing pulling at the edges of your attention and ruining the experience. I quite like it.
Because I write with an overly-large number of asides, I fell in love with the Tufte-styled side/margin notes. The resulting text is much easier to read, since I'm not littering the paragraphs with em-dashes and lengthy parentheticals.
I hope more people rebel against the Medium-looking websites with massive images and huge blocknotes in 30px fonts that may or may not just be a line from the next paragraph or an important point to keep in mind when reading the next paragraph.
Edit: Ah, it's an extension to Python-Markdown that is not enabled by default: https://python-markdown.github.io/extensions/smarty/