.overlay-zoom {
    position:absolute;
    bottom:8px;
    left:50%;
    transform:translateX(-50%);
    background:rgba(0,0,0,0.5);
    color:#fff;
    font-weight:bold;
    font-size:12px;
    padding:4px 8px;
    border-radius:5px;
    opacity:0.85;
    transition:0.2s;
    text-shadow: 0 0 3px rgba(0,0,0,0.8);
}

a:hover .overlay-zoom {
    opacity:1;
    background:rgba(0,0,0,0.75);
}