@page {
  size: 640px calc(640px * sqrt(2));
  margin: 0px;
  padding: 0px;
}

div.poster {
  position: relative;
  margin: 0px;
}

div.poster {
  width: calc(640px - 0.75em - 0.75em);
  height: calc(640px * sqrt(2) - 0.75em - 0.75em);

  padding-left:   0.75em;
  padding-right:  0.75em;
  padding-bottom: 0.75em;
  padding-top:    0.75em;
}