Set custom column for mobile and tablet

Hello,
I have a problem with your equal heights columns, I cant figure out how to make the number of column change on tablet and mobile.
When NOT using the equal height option for the column, you can use the following CSS, but with equal height activated, there seems to be a completely different structure, which I have had NO luck in figuring out how to seperate.

@media only screen and (min-width: 1px){
div .av_one_fifth {
width: 45% !important;
margin-left: 2% !important;
}

@media only screen and (min-width: 768px){
div .av_one_fifth {
width: 31% !important;
margin-left: 2% !important;
}

@media only screen and (min-width: 1200px){
div .av_one_fifth {
width: 18% !important;
margin-left: 2% !important;
}