.banner {
    position: relative;
    overflow: hidden;
    width: 860px;
    height: 260px;
    box-shadow: 0px 0px 14px #888888;
}

.banner ul {
    padding: 0;
    margin: 0;
}

.banner ul li {
    float: left;
    overflow: hidden;
    width: 860px;
    height: 260px;
    list-style: none;
}
.banner a .arrow {
    position: absolute;
    width: 20px;
    height: 35px;
    top: 120px;
}

.al {
    left: 15px;
}

.ar {
    right: 15px;
}