#xyz_main {
    width: 803px;
    height:600px;
    /*border: 1px solid #666666;*/
    text-align: left;
    position: absolute;
    top: 50%;
    left: 50%;
    margin-left: -401px;
    margin-top: -300px;
}
#xyz1024_main {
    width: 1024px;
    height:768px;
    border: 1px solid #666666;
    text-align: left;
    position: absolute;
    top: 50%;
    left: 50%;
    margin-left: -512px;
    margin-top: -384px;
}