@j12i This morning I kept trying with "64em;" and it didn't work, while "1000px" with the semicolon accidentally (but correctly) elided did work. 🤦🏻♀️
Now as you try to zoom in and out you'll see the margin notes pop in and out correctly.
For 1.5 on your width, they belong inside the text ♥
This is a bug in all browsers I've tried with, or maybe it's a shortcoming in the spec itself: I want to set the media min-width selectors to use em (as in, a certain number of letters at the users chosen zoom level), not px, but that isn't supported.
Maybe I can use calc somehow? 🤔