.w{
    width: 1000px;
    margin: 0 auto;
    position: relative;
}
.box{
    background-color: #eee;
}
.boxlv{
    background-color: #3c8cc9;
}
.z{
    text-align: center;
}
.fl{
    float: left;
}
.fr{
    float: right;
}