*{ padding:0px; margin:0px;list-style:none;}
.ad {
    width:100%;
    height:95px;
    margin:5px auto;
    position:relative;
    overflow:hidden;
}
.ad .slider{
    width:400%;
    position:absolute;
    left:0px;
    top:0px;
}

.ad .slider li{
    float:left;
    width: 25%;
}
.ad .slider li a{
    display: block;
    width: 100%;
    height: 95px;
}
.ad .num {
    position:absolute;
    width:100%;
    bottom:10px;
    left:0px;
    text-align:center;
    font-size:0px;
}
.ad .num li {
    width:10px;
    height:10px;
    background-color:#888;
    border-radius:50%;
    display:inline-block;
    margin:0px 3px;
    cursor:pointer;}
.ad .num li.on {
    background-color: #ff6a00;
}
.ad .btn {
    width: 30px;
    height: 50px;
    background-color: #808080;
    opacity: 0.5;
    filter:alpha(opacity:0.5);
    position:absolute;top:50%;
    margin-top:-25px;
    cursor:pointer;
    text-align:center;
    line-height:50px;
    font-size:40px;
    color:#fff;
    font-family:"宋体";
    display:none;
}
.ad .btn_l {
    left:0px;
}
.ad .btn_r {
    right:0px;
}
.ad:hover .btn {
    display:block;
}