One-line: a recessed tray whose header/footer sit on the muted surround and whose content sits on a raised panel.

```jsx
<Frame>
  <FrameHeader><FrameTitle>Preview</FrameTitle><FrameDescription>How attendees see this page.</FrameDescription></FrameHeader>
  <FramePanel>…</FramePanel>
</Frame>
```
