Design is about choices. In this case you can point out:
1. top-left square logo, dark gray, slab serif, fixed on scroll
3. bold, large sans-serif title in "off-black"
4. large serif body text with extended line-height
5. 100% width image on top
Despite the visual simplicity, there are a lot of variables in effect. It's definitely "inspired" by Medium.
I think that the lack of author information in the top left is sufficiently different to not even call it gray area. And the lack of paragraph-level comments.
The logo and typography seem very similar, even to my untrained eye, though.