How to stretch to the width of a column in Flexbox?

Question

Flexbox

How to do it right on flex ?
cells in 3 rows are stretched over the entire container and there is a gap between them, as in a grid, for example. 20px
in what to set the sizes? in percentages?

Answer 1

You can give them a margin on the sides and put justify-content: space-between on the parent block.
And look at the sizes there yourself, you can put 30% each.
https://tpverstak.ru/flex-cheatsheet/