[css-grid-2] Cross-reference subgrid alignment. #7078

Author: fantasai

css-grid-2/Overview.bs

@@ -4034,6 +4034,11 @@ Alignment and Spacing</h2>
 	and the dimensions of all <a>grid items</a> are finalized,
 	<a>grid items</a> can be aligned within their <a>grid areas</a>.
 
+	Note: The [=grid items=] of [=subgrids=] participate in alignment,
+	including [=baseline alignment=],
+	together with their [=parent grid=]'s items;
+	see <a href="#subgrid-item-contribution">Subgrids (h)</a>.
+
 	The 'margin' properties can be used to align items in a manner similar to
 	what margins can do in block layout.
 	<a>Grid items</a> also respect the <a>box alignment properties</a>