One column grid gallery layout for mobile view only - code help needed.

Hello!

I need some help - I'm looking to make a one-column grid for mobile view only on the page https://www.patrickfogarty.com/properties-test - I've upgraded the section to 7.1 (was previously 7.0 but I've upgraded the site since) but most of the code I find doesn't seem to help.

Here's what I have in the custom CSS panel as of now, in case theres any interactions:

body.homepage header#header img {
    visibility: hidden;
}

#wm-sidebar-nav{
  padding-right: 35px
}

footer {
    font-size: 10px;
}

Thank you very much in advance! 🫡

This plugin from Ghost Plugins should help!

Thanks for the suggestions, @rishachesterfield - but it doesn't seem to be working on my end. Is it on yours? I'm fully prepared for this to be a cache issue.