Firefox Update – wp-block-gallery columns-4 Problem

Hi there,

might be worth reporting that to WordPress, as its to do with their super convoluted CSS method to work that grid.
For now you could just overwrite the grid with some CSS Grid:

.wp-block-gallery.columns-4 {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
}
.wp-block-gallery.columns-4 > .wp-block-image {
  width: 100% !important;
}

@media(max-width: 800px) {
  .wp-block-gallery.columns-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

You do have some CSS in your child theme that sets the gallery image width which will need removing as the images need to be 100% on all screen sizes