body{margin:0;padding:0;background-position:top center;background-repeat:no-repeat;background-attachment:fixed}#flex-wrapper{width:100%;height:100%;overflow:hidden;position:fixed;top:0px;left:0px;z-index:-1}#flex-wrapper img{position:absolute;top:0;left:0;opacity:0;z-index:0;display:block}#flex-wrapper img.active{z-index:10}