This can also be achieved with the CSS "Order" property and a media query.
Something like this:
@media only screen and (max-width: 768px) {
#first {
order: 2;
}
#second {
order: 4;
}
#third {
order: 1;
}
#fourth {
order: 3;
}
}
CodePen Link: https://codepen.io/preston206/pen/EwrXqm