[css-sizing-4] "scroll container" probably needs to be more precise.

[bfgeek]

https://drafts.csswg.org/css-sizing-4/#aspect-ratio-minimum

It is possible for something to be a scroll container along one axis, e.g. "overflow-x: auto". This rule probably only wants to apply when the "ratio-dependent axis", is the same as the scroll container axis?

[Loirooriol]

It's not possible, see https://drafts.csswg.org/css-overflow-3/#overflow-properties

Only the visible and clip values avoid a scroll container, and

Computed value: as specified, except with visible/clip computing to auto/hidden (respectively) if one of overflow-x or overflow-y is neither visible nor clip.

The overflow-x: auto that you mention behaves as either scroll or hidden, both of which make a scroll container (even if there is no scrollbar, you can scroll with JS).