*{
        margin: 0;
        padding: 0;
    }
    .w{
        width:1230px;
        margin:0 auto;
    }
    li{
        list-style: none;
    }
    a{
        text-decroation: none;
    }
    .header{
        height: 42px;
        margin:30px auto;
    }
    .logo{
        float: left;
        width: 198px;
        height: 42px;
    }
    .nav{
        float: left;
        margin-left: 50px;
    }
    .nav ul li{
        float: left;
        margin: 0 15px;
    }
    .nave ul li a{
        display: block;
        height: 42px;
        padding: 0 10px;
        line-height: 42px;
        color: black;
    }
    .nave ul li a: hover{
        border-bottom: 2px solid #00a4ff;
    }
    .search{
        float: left;
        width: 412px;
        height: 42px;
        background-color: #00a4ff;
        margin-left: 50px; 
    }
    .search input{
        float: left;
        width: 345px;
        height: 40px;
        border: 1px solid #00a4ff;
        border-right: 0;
        color: #bfbfbf;
        font-size: 14px;
        padding-left: 15px;
    }
    .search button{
        float: left;
        width: 50px;
        height: 42px;
    /* 去掉按钮默认边框 */
        border: 0;
        background: url(images/btn.png);
    .user{
        float: left;
    }