.cb-background li {
 list-style-type: none;
}
.cb-background li span { 
    width: 100%;
    height: 100%;
    position: fixed;
    top: 0px;
    left: 0px;
    color: transparent;
    background-size: cover;
    background-position: 50% 50%;
    background-repeat: none;
    z-index: 0;
}

.cb-background li:nth-child(1) span { 
    background-image: url(../images/slideshow/slide003.jpg); 
}

?>