Index gallery stack on tablet

Hi, I have a gallery within an index page that I need to stack on tablet. It views fine on mobile, albeit I need to also get rid of a white space area (see screenshot).

The tablet view cuts off all info and I would just like it to feature 1 column, not 3.

Any help here would be most appreciated! Thanks!!

What is page url? We can check easier

Thanks for your reply tuanphan. The page of concern is the homepage - you can view here https://www.maharishischool.vic.edu.au/ or here https://maharishischool.squarespace.com/ for in-built domain (not sure which you need).

Thank you

Add to Design > Custom CSS

/* Tablet Stacked Columns */
@media screen and (max-width:900px) and (min-width:641px) {
section#info-home article.Index-gallery-item {
    width: 100% !important;
}
body, html {
    overflow-x: hidden;
}
}

Thank you ~ it stacked the gallery on tablet view however there is now a double scroll bar on the right. When I remove the code it goes back to normal. Any way of fixing this?