I wish this had max-width: 60ch (or at least 80ch). I have some difficulties in reading and keeping my attention past 60-80ch line width wall of texts. Sometime I manually edit the CSS to make line shorter, so that I can keep reading.
It does set max-width of .comment and .toptext to 40em. Which means items on the page can nest across the screen, but each one will be no wider than that.
I took my cue from https://design-system.service.gov.uk/ where the majority of their design decisions are informed by thorough extensive user research. They set their text elements to a max width of 38em. That felt a little mean to me so I upped it to 40.
