[kaapipo]

I have always thought `em` is the line height?

I didn't know about `ch` and `ex`, I'm gonna try them

[chrismorgan]

The default line height is defined by the font (and the browser may influence it in other ways too?), but it’s distinct from the em. (It’s easy to try in a browser. I see values like 18.78px and 19.33px and 21.67px on my 16px text.)