#div {
  margin: 0px auto 0px auto;
  text-align: center;
  width: 631px;
  height: 407px;

    position:absolute;
    top:50%;
    left:50%;
    margin-top:-204px;
    margin-left:-316px;
    width:624px;
    height:394px;
}

#div2 {
  margin: 0px auto 0px auto;
  text-align: center;
}