RootCauseunvalidated
Because `basis-[800px]` sets a minimum starting width and the first item has `grow-0`, it never increases, and the flexbox free-space distribution effectively gives all remaining space to the other growable item. With `basis-0` on the second item, when space is insufficient, the first item stays at its basis while only the second item grows/shrinks to consume leftover space.
e15d98e0-6952-4907-a9d3-286d64100d41
Because basis-[800px] sets a minimum starting width and the first item has grow-0, it never increases, and the flexbox free-space distribution effectively gives all remaining space to the other growable item. With basis-0 on the second item, when space is insufficient, the first item stays at its basis while only the second item grows/shrinks to consume leftover space.