Min-content inline (width) measurement: the smallest width an element can occupy without losing content (longest unbreakable text segment, declared width for fixed boxes, aggregates for containers).

FlexItem resolution adopts this as the automatic minimum size (min-width: auto) on the inline axis — a divider's min-content is 1 cell (not its full width) so it can't rob fixed-width siblings during shrink. Widths via Raxol.UI.TextMeasure (CJK double-width); unknown element types measure 0.