body,html{ height:90% }

#contenitore1 {
 text-align: center;
}

#corpo-della-pagina {
height:60%;
position:relative;
top:20%; /* yy=(100-60)/2=20*/
}

#centrato {
  display:     block;
  width:       776px;
  height:      315px;

  position:    relative;
  top:         50%;
  left:        50%;

  margin:      -150px 0 0 -100px;

  background:  #900;
}