How to fit one item per line when (max-width: 767px) is reached, using flex-box technology?

Question

css

How to fit one item per line when (max-width: 767px) is reached, using flex-box technology?

I know that to indicate the achievement (max-width: 767px) - media is used.
Flex-box is used because it was originally specified (display: flex).

Answer 1

In the media query, specify for the desired block flex-basic: 100%;
Or for a parent block with display: flex; specify flex-direction: column;
This is if I understand the question correctly.