.header
{
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  z-index: 2;
  height: 3em;
  overflow: hidden;
  padding: .5em;
  color: #fff;
  line-height: 1.2;
  background-color: #0e5bb8;
  border-bottom: solid 1px #ddd;
  box-shadow: 1px 1px 10px #333;
}
.iframe
{
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 1;  
  width: 100%;
  min-height: 100%;
  padding-top: 4em;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}