#slides {
    position: relative;
    height: 300px;
    padding: 0px;
    margin: 0px;
    list-style-type: none;
}

.slide {
    position: absolute;
    left: 0px;
    top: 0px;
    width: 100%;
    height: 100%;
    opacity: 0;
    z-index: 1;

    -webkit-transition: opacity 0.3s;
    -moz-transition: opacity 0.3s;
    -o-transition: opacity 0.3s;
    transition: opacity 0.3s;
}

.showing {
    opacity: 1;
    z-index: 2;
}