How do you add a border to product item gallery slide images?

How do you add a boarder to product item gallery slide images?

I have tried the following code, but the border only appears on the left and top edge of the images:

.ProductItem-gallery-slides-item{ border:1px solid black !important; }

Any help would be appreciated.

Site: https://echidna-mandolin-33c8.squarespace.com/shop/p/mangawhai
PW: hello

It looks like you solved with this new CSS code

div.ProductItem-gallery-slides {
    border: 1px solid #e5e5e5;
}