Background:
On longpages or compact content layouts, there is often a need for expandable single sections for supplementary content such as transcripts, glossaries, or additional information. An accordion widget is overkill for this purpose, as it requires multiple tabs and semantically implies a group behavior.

Problem:
- The Accordion widget cannot currently be reduced to a single tab.
- Using a "pseudo-accordion" with only one panel is semantically incorrect and may negatively impact accessibility and user orientation.
- There is no dedicated widget to toggle individual content sections, making implementation cumbersome.

Suggestion:
A dedicated widget based on the established HTML5 <details>/<summary> pattern or a disclosure element. It should:
- Toggle a single content block open/closed
- Optionally scroll automatically
- Optionally support state persistence
- Clearly indicate visual states
- Be configurable via GUI and designOption.json