"Giving an element inline-size containment has no effect if any of the following are true:

if the element does not generate a principal box (as is the case with display: contents or display: none)
if its inner display type is table
if its principal box is an internal table box
if its principal box is an internal ruby box or a non-atomic inline-level box"

https://drafts.csswg.org/css-contain-3/#containment-inline-size