#flipbook {
    position: relative;
    width: 272px;
    height: 450px;
    margin: 0 auto 10px auto;
}

#flipbook IMG {
    position: absolute;
    top: 0;
    left: 0;
    width: 272px;
    height: 450px;
    z-index: 8;
    opacity: 0.0;
}

#flipbook IMG.active {
    z-index:10;
    opacity: 1.0;
}

#flipbook IMG.last-active {
    z-index:9;
}