轮播图圆点自适应居中问题

html：

<div class="slideBox">

    <div class="hd">

        <ul>

            <li></li>

            <li></li>

            <li></li>

            <li></li>

            <li></li>

        </ul>

    </div>

    <div class="bd">

        <ul>

            <li><a target="_blank" href="http://www.baidu.com"><img src="./image/banner1.png" /></a></li>

            <li><a target="_blank" href="http://www.baidu.com"><img src="./image/banner1.png" /></a></li>

            <li><a target="_blank" href="http://www.baidu.com"><img src="./image/banner2.png" /></a></li>

            <li><a target="_blank" href="http://www.baidu.com"><img src="./image/banner2.png" /></a></li>

            <li><a target="_blank" href="http://www.baidu.com"><img src="./image/banner3.png" /></a></li>

        </ul>

    </div>

</div>

---

css：

.index-box .left .slideBox .hd{

    height:15px;

    overflow:hidden;

    position:absolute;

    bottom:5px;

    z-index:1;

    left: 0;

    margin: 0 auto;

    width: 100%;

}

.index-box .left .slideBox .hd ul{

    text-align: center;

    overflow:hidden;

    zoom:1;

    position: absolute;

    width: 100%;

}

.index-box .left .slideBox .hd ul li{

    margin:0 2px;

    width:11px;

    height:11px;

    -webkit-border-radius: 50%;

    -moz-border-radius: 50%;

    border-radius: 50%;

background:rgba(255,255,255,.4);

    cursor:pointer;

    display: inline-block;

}