HTML+CSS实现手风琴样式

HTML:

<body>
    <div class="box">
        <ul>
            <li class="pic1"><a href="#"> <span></span> <b>度假酒店 </b> </a></li>
            <li class="pic2"><a href="#"> <span></span> <b>度假酒店 </b> </a></li>
            <li class="pic3"><a href="#"> <span></span> <b>度假酒店 </b> </a></li>
            <li class="pic4"><a href="#"> <span></span> <b>度假酒店 </b> </a></li>
            <li class="pic5"><a href="#"> <span></span> <b>度假酒店 </b> </a></li>
            <li class="pic6"><a href="#"> <span></span> <b>度假酒店 </b> </a></li>
            <li class="pic7"><a href="#"> <span></span> <b>度假酒店 </b> </a></li>
        </ul>
    </div>
</body>

CSS:

<style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 1200px;
            height: 260px;
            border:1px solid #000;
            margin: 0 auto;
            margin-top:50px;
        }
        .box ul li{
            float: left;
            width: 14.28%;
            height: 260px;
            text-align:center;
            list-style: none;
        }
        .box ul li a{
            text-decoration:none;
            width: 100%;
            height: 100%;
            display: block;
            position: relative;
        }
         .box ul li span{
            display: block;
            width: 100%;
            height: 100%;
            background-color: #000;
            opacity: .5;
        } 
        b{
            font-size: 28px;
            display: block;
            width: 30px;
            color: #fff;
            position: absolute;
            left: 0;
            right: 0;
            top: 30px;
            margin: auto;
        }
        .box:hover li{
            width: 133px;
        }
        .box li:hover{
            width: 400px;
        }
        .box li:hover span{
            display: none;
        }
        .box li:hover b{
            display: none;
        }
        .pic1 a{background: url(./images/img_1.png) center no-repeat;}
        .pic2 a{background: url(./images/img_2.png) center no-repeat;}
        .pic3 a{background: url(./images/img_3.png) center no-repeat;}
        .pic4 a{background: url(./images/img_4.png) center no-repeat;}
        .pic5 a{background: url(./images/img_5.png) center no-repeat;}
        .pic6 a{background: url(./images/img_6.png) center no-repeat;}
        .pic7 a{background: url(./images/img_7.png) center no-repeat;}
    </style>