GP is also wrong anyway, CSS Flex is the wrong thing for creating layouts like this. We now have CSS Grid, which is the actual replacement for table-based layouts (which were used more recently than people like to admit because of Flex not working for two-dimensional layouts).
Sorry, I often conflate flex and grid, they occupy the same spot in my mind as “1 dimensional” and “2 dimensional” versions of the same underlying thing. I am wrong.
