div.block-layered-nav, div.amshopby-page-container, div.amshopby-filters-top {
    position: relative;
}

div.amshopby-overlay {
    background: #fff url(../images/amshopby-overlay.gif) no-repeat center center;
    height: 100%;
    left: 0;
    opacity: 0.5;
    position: absolute;
    top: 0;
    width: 100%;
    z-index: 555;
}