Footer Navigation Columns on Mobile

Site URL: https://www.boutique14.co.uk/home1

Hi, trying to configure the footer navigation. I am happy with a centered stacked layout on desktop, but on mobile it's all bunched too closely together and I'm concerned about accessibility because the links are too close together. It would be good if on mobile only I could either space the links out more, or use columns. I'm messing about with this CSS:

@media screen and (max-width: 640px) {

  .Footer-bottom {
    layout: columns
  }
}

It doesn't work. Could do with some help please. Thank you.

Add to Home > design > Custom CSS

@media screen and (max-width:640px) {
.Footer-nav-group {
    display: flex !important;
}
}

Fantastic! Thank you.