* {
  box-sizing: border-box;
}

/* Define max image width and height */
:root {
  --max-img-width: 600px;
  --max-img-height: 400px;
}

img {
  max-width: 100%;
  vertical-align: top;
}

.gallery {
  display: flex;
  position: relative;
  padding-top: 820px;
}
.gallery img.gallery__img {
  width: 100%;
}
.gallery__img {
  position: absolute;
  top: 0;
  left: 0;
  opacity: 0;
  transition: opacity 0.3s ease-in-out;
}

.gallery__thumb {
  padding-top: 6px;
  display: block;
  cursor: pointer;
}

.gallery__selector {
  position: absolute;
  opacity: 0;
  visibility: hidden;
}

.gallery__selector:checked + .gallery__img {
  opacity: 1;
}

.gallery__selector:checked ~ .gallery__thumb > img {
  box-shadow: 0 0 0 3px #f6ce0b;
}

@media screen and (min-width: 1280px) {
  .gallery {
    width: 80%;
    margin-left: auto;
    margin-right: auto;
  }
}