SHOWCASE THEME - Rounded Corners on Listing Photos

Hello hello! I’m wanting to add rounded corners to my listing photos, including on hover. I’ve looked through many threads but they’re all pretty theme-specific and dependent on code structure.

I tried using my very limited coding knowledge to try and figure out where/how I should do this, and I can’t seem to find the place! Or if I did, it’s possible the code I added isn’t compatible with my theme.

.w-full {
    width: 100%;
    border-radius: 50px !important;
}

.product-item-hover {
width: 100%;border-radius: 20px !important;
}

is the code I tried inserting at the end of style.liquid and theme.liquid.

If anyone can help me i’d be super grateful!