Can't get older gallery page to display as a grid

I'm using the 7.0 Flatiron template.  A gallery page I made years ago is no longer displaying the images as a grid, just as a giant stack now.  When I click "edit" on the page, nothing happens.

How can I get the images on this page to display as a grid again?

https://www.kwerling.com/art-direction

pw: photography

You try this to Website Tools > Custom CSS

@media screen and (min-width:901px) {
.gallery {
    display: grid !important;
    grid-template-columns: repeat(4,1fr) !important;
    grid-gap: 10px 10px;
}
}