#Download {
    width: 1464px;
    height: 172px;
    text-align: center;
    position: absolute; 
    left: 50%;
    margin-left: -476px;
    z-index: 51;
    border-radius: 5px;
    background: url(../image/down.png) no-repeat left top;
}
#Download .btn_down_s1 {
    float: left;
    width: 320px;
    height: 87px;
    text-indent: -999em;
    margin-left: 0px;
    margin-top: 43px;
}
#Download .btn_down_s2 {
    float: left;
    width: 320px;
    height: 87px;
    text-indent: -999em;
    margin-left: 10px;
    margin-top: 43px;
}
#Download .btn_down_s3 {
    float: left;
    width: 320px;
    height: 87px;
    text-indent: -999em;
    margin-left: 10px;
    margin-top: 43px;
}
#Download .btn_down_s4 {
    float: left;
    width: 120px;
    height: 89px;
    text-indent: -999em;
    overflow: hidden;
    margin-left: 13px;
    margin-top: 42px;
}