Received good advice on Discord:
find all instances in the left snippet where it has the selector
.calloutand change those to.callout.is-collapsible
and if you want to be really explicit, you also would take all instances in the right snippet of
.calloutand change them to.callout:not(.is-collapsible)
But wasn’t successful in reconciling the two snippets. Ran into issues with inconsistent appearance between collapsible and non-collapsible callouts, with the latter having weird padding and white background still in some places… Don’t really know CSS to troubleshoot 