maguisiffredi

Have a read of this, the easiest way is to use a chrome extension:
https://squarefortytwo.com/squarespace-guides/find-an-id-in-squarespace-71

@Ziggy Perfect! Works like a charm 🙂
Just out of curiosity, how do you get the ID number? Just in case I make another project with this module, I can add it to this code. 
Thanks very much!

Here's Custom CSS that targets those two pages:
// 3 column gallery #item-62f62b5f93c4937c416abc70, #item-655f657d4a82a13e7b94a4c0 { .gallery-grid-wrapper { grid-template-columns: repeat(3, 1fr) !important; } } You can add more pages by adding more comma-separated page/item IDs.

Thanks for your answer @Ziggy. I tried it and it worked 🙂 But as you said, it applies to all projects, and I just want to apply it to certain projects where I use this design. Is it possible to target this to a project in particular? 
Thanks very much!

You can use CSS like this to force the gallery to stay at 3 wide, but you'll need to target this to certain sections or collections depending on how consistent your galleries are. 
.gallery-grid-wrapper { grid-template-columns: repeat(3, 1fr) !important; }