Watermark for photos in gallery image block

Site URL: https://the3dbabyco.squarespace.com/photo-gallery

Hi there, I am using the following code to add an automatic watermark to my gallery images. I cannot get this to work with the gallery grid block (it worked great with the gallery section). Can I get some help adjusting this code for the block? thanks! 

page password: scocreativeclient

Code: 

.sqs-gallery-block-grid {
    position: realtive!important}

.gallery-grid-item-wrapper:after{
    content: " ";
    display: block;
    background-image: url(https://static1.squarespace.com/static/6189804068b54844ea21fc1f/t/622902cc23410f21df68e58b/1646854861070/The-3D-Baby-Co---Round-Pale-Yellow.png)!important;
    background-size: contain;
    position: absolute;
    width: 60px;
    height: 60px;
    right: .5rem;
    bottom: .5rem;
    opacity: .5
}

Use this code for Gallery Block

.gallery-block .slide .margin-wrapper:after {
    content: " ";
    display: block;
    background-image: url(https://static1.squarespace.com/static/6189804068b54844ea21fc1f/t/622902cc23410f21df68e58b/1646854861070/The-3D-Baby-Co---Round-Pale-Yellow.png)!important;
    background-size: contain;
    position: absolute;
    width: 60px;
    height: 60px;
    right: .5rem;
    bottom: .5rem;
    opacity: .5;
}
.margin-wrapper {
    position: relative;
}

This worked perfect! Thank you sooo much