body{
    padding:0;
    margin:0;
    text-align: center;
}

#mainCont{
    position: relative;
    margin: 0 auto; 
    width:1000px;
    height: 700px;
}

#mainContIn{
    position: absolute;
    top:0;
    left:0;
    width:1000px;
    height: 700px;
}