7.0 Wells - Code to get mobile galleries to be 2 column masonry

I would like my image galleries to be 2 column masonry galleries on mobile. My site is Wells 7.0. Can anyone help?

My site is: www.joycoakley.com

You try using this code to Website > Website Tools (under Not Linked) > Custom CSS

@media screen and (max-width:640px) {
div#page-5824f789b8a79b97633af6be .span-12>.row {
    column-count: 2;
}
}