A - or + after the type makes the callout foldable.
> [!question]- Folded (minus)
>
> Only appears when unfolded.
> [!question]+ Unfolded (plus)
>
> Starts open, can be folded away.Folded (minus)
Only appears when unfolded.
Unfolded (plus)
Starts open, can be folded away.
In this template
The title is the control. It therefore gets a focus ring of its own in the type colour — out of the box it is clickable but not recognisable as a control from the keyboard.
The arrow turns when unfolding; with prefers-reduced-motion on it jumps instead.
Folded content is still in the document
Anyone searching or printing the page gets the folded text too. Foldable means “tidy”, not “hidden”.