#popup {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
}

#popup img {
  display: block;
  max-width: 100%;
  max-height: 100%;
  margin: auto;
  margin-top: 5%;
}

#closePopup {
  position: absolute;
  top: 10px;
  right: 10px;
}