#Download {
    width: 830px;
    height: 265px;
    text-align: center;
    position: absolute;
    top: 840px;
    left: 50%;
    margin-left: 0;
    z-index: 51;
    border-radius: 5px;
}

#Download .btn_down_s1 {
    float: left;
    width: 90px;
    height: 265px;
    text-indent: -999em;
        margin-left: 0;
    animation: sc 2s infinite linear;
}

#Download .btn_down_s2 {
    float: left;
    width: 90px;
    height: 265px;
    text-indent: -999em;
    margin-left: 62px;
    animation: sc 2s infinite linear;
}
#Download .btn_down_s3 {
    float: left;
    width: 90px;
    height: 265px;
    text-indent: -999em;
    margin-left: 72px;
    animation: sc 2s infinite linear;
}
#Download .btn_down_s4 {
    float: left;
    width: 90px;
    height: 265px;
    text-indent: -999em;
    margin-left: 64px;
    animation: sc 2s infinite linear;
}