.google_map{
  float:left;
  display:inline;
  position:relative;
  width:100%;
  height:0px;
  padding-bottom:35%;
}

.google_map iframe{
  position:absolute;
  top:0px;
  bottom:0px;
  left:0px;
  right:0px;
  width:100%;
  height:100%;
}