The idea
content-visibility: hidden skips rendering an element's contents entirely — like display: none, but the element itself stays in the layout. It also applies size containment, so the box collapses to zero height. (content-visibility: auto does the same, but only for off-screen content.)
height (and min-height/max-height) are off-limits: the collapse must come from content-visibility, not a hardcoded height.