.fullscreen {
  display: none;
  position: absolute;
  z-index: 9999;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, .7);
}
.popup {
  position: absolute;
  z-index: 99999;
  top: 50%;
  left: 50%;
  width: 640px;
  height: 360px;
  margin: -240px 0 0 -380px;
}