One thing that came up at the extensible Web summit in Boston on Friday was a discussion of container queries.

While I'd previously suggested tying container queries to CSS containment, one thing I realized is that there will be cases where developers want to fix the width from the outside but still allow an auto height, and then do media queries on the container's width.

I haven't thought this through very much, but it seems to me that this may require a concept of layout containment in a single dimension to be exposed from containment.