Add a transparent overlay on top of Flatshop product backgrounds. Kudos to Christian!

gistfile1.css

.products .product:before,
.single .product-single-top:before {
    content: " ";
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    background: rgba(255,255,255,.4);
    z-index: 1;
}
.list-post .summary,
.single-product .summary,
.products .product .transition-one-up,
.products .product .no-transition,
#product_single_wrapper {
    z-index: 2;
    position: relative;
}
#headerwrap {
    z-index: 10;
}
.product-image {
    z-index: 10;
}