* {
        margin: 0;
        padding: 0;
    }
    
    ul {
        list-style: none;
    }
    
    a {
        text-decoration: none;
    }
    /*采用固定布局*/
    
    #nav {
        position: fixed;
        left: 95%;
        bottom: 5px;
    }
    
    #nav a i {
        display: none;
    }
    
    #nav a {
        display: block;
        background: white;
        width: 48px;
        height: 54px;
        box-shadow: 0 0 8px #ccc;
        -webkit-box-shadow: 0 0 8px #ccc;
        -moz-box-shadow: 0 0 8px #ccc;
        border-bottom: 2px solid gray;
        border: 2px solid gray;
    }
    
    #nav img {
        padding-left: 10px;
        padding-top: 15px;
        width: 25px;
        height: 25px;
        line-height: 25px;
    }
    
    #nav a:hover img {
        display: none;
    }
    
    #nav a:hover i {
        display: block;
        width: 35px;
        padding-left:5px;
        padding-top: 8px;
        text-align: center;
        color: #F93;
    }
    
    #nav span img {
        display: none;
    }
    
    #nav a:hover span img {
        padding-left: 0px;
        padding-top: 0px;
        position: relative;
        display: block;
        top: -170px;
        right: 207px;
        width: 200px;
        height: 200px;
        border: 2px solid #ccc;
    }