css for responsive behaviour

Hello css experts
I have a page that breaks when the browser width is less than around 400px

I'm using bootstrap and a row has 4 colums

I would like for you to add a different behaviour
when the width is less than around 400px
so that each column becomes a row
(one element on top of the other, instead of being horizontal)

Attaching screenshots of the current broken page
and how i would like it to be

Thank you