Worked reference · Semantic table + embedded layout
Keep the comparison intact inside its real frame.
The child document owns the comparison and its native relationships. The parent page owns preview placement, contextual title, sandbox, and the route to this full view. Those responsibilities meet through an observable boundary rather than becoming one layout guess.
| Layer | Owner | Visitor ability | Observable result |
|---|---|---|---|
| Parent composition | Parent page | Understand why the preview is present and continue to a full view. | A contextual iframe title and direct onward link remain available. |
| Embedded boundary | Parent-and-child contract | Operate the preview at the width the child actually receives. | Frame width, child width, local scrolling, focus, and paint clearance can be observed separately. |
| Comparison meaning | Child document | Compare each layer against the same set of fields. | Caption, column headers, row headers, and literal values retain their relationships. |
| Full view | Canonical child route | Continue beyond the compact preview with the comparison intact. | The same source-owned child opens independently of the parent's preview height. |