.hidden {
  display: none;
}

#gallery {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
  text-align: center;
}

#galleryImage {
  max-width: 90%;
  max-height: 90%;
  margin-top: 5%;
}

#prev, #next {
  cursor: pointer;
  position: absolute;
  top: 50%;
  width: auto;
  margin-top: -30px;
  padding: 16px;
  color: white;
}
#prev {
  left: 0;
}
#next {
  right: 0;
}
.close-btn {
  cursor: pointer;
  position: absolute;
  top: 10px;
  right: 10px;
  width: auto;
  padding: 16px;
  color: white;
  font-size: 30px;
}