How can i force a "project" to 2 across on mobile?

Site URL: https://tmha-new-site.squarespace.com/galleries

https://tmha-new-site.squarespace.com/galleries

password: tamara

I'm trying to make mobile have 2 galleries across so its like 2 by 2 with minimal padding inbetween the rows. Is this possible? Its currently 4 on desktop but id like 2 across on mobile

Add to Galleries Page Header

<!-- Mobile 2 columns -->
<style>
  @media screen and (max-width:767px) {
  div#gridThumbs {
    grid-template-columns: repeat(2,1fr) !important;
}
  }
</style>