How to set character limit per line in blog posts?

Aside from wrapping ordered and unordered lists in a class and then setting max-width: X characters and margin: auto, is there any other (easier) way to set a character limit per line in the body of a post?

This would be implemented a theme, so you could research what’s possible with CSS.

According to this, you might have some luck with specifying a value in ch (character) or em (em-dash) units: