How do I make a div stretch in a flexbox of dynamic height?
问题 I'm trying to make a stacked layout using flexbox. Ideally it'd look like this: where the bottom (blue) div is a fixed height of 250px and the top div is n-250 , where n is the size of the parent container--in another words, the top should stretch to fill the container. I have some idea of how to do this when I have the container height, but I'd rather avoid having to determine that variable at runtime. This issue has been covered at length in various forms , but none seem to address this