Have you considered displaying comment and plot side by side, so that both are visible at all times without having to scroll on smaller screens?

Yes. That's exactly what I've done here, in fact: https://www.marksmath.org/visualization/trig_sum.html Generally, I prefer not to worry about layout in the notebook and rather defer that to any webpage where I embed the visualizations. Having said that, I definitely whipped this notebook up pretty fast as a demo for my calculus class and should've layed out the positioning of the labels within the diagram with more care so I could easily change the aspect ratio.

A quick workaround would be to reparent the elements: html`<div>${viewof take_step} <div style="display:flex;flex-wrap:wrap"> <div style="min-width:10em;flex:.5">${comment}</div> <div style="min-width:400px;flex:1">${diagram}</div>`

Well, two years and one week later, I took your advice!