body {
  width: 100%; height: 100%;
  margin: 0; padding: 0; 
  text-align: center; /* use text-align to make IE in quirks mode centre the divs */
}

div#centered
{
width: 766px; /* see note below about widths */
margin: 0 auto; 
padding: 0; /* margin 0 auto centres the divs horizontally for FF, Opera,*/
}