gallery/style/gallery.css

@import url(base.css);

body {
  --image-size: 200px;
  --grid-gap: 1.5em;
  --max-cols: 4;

  max-width:
    calc(var(--max-cols) * var(--image-size) +
         (var(--max-cols) - 1) * var(--grid-gap) +
         4em);
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, var(--image-size));
  grid-gap: var(--grid-gap);
  justify-content: center;
  justify-items: center;
  align-items: start;

  padding: 0;
  margin: 0;
}

.item {
  --shadow-size: 10px;
  --border-thickness: 2px;

  position: relative;
  width: var(--image-size);
  height: var(--image-size);
  padding: 0;
  margin: 0;

  list-style: none;

  box-shadow: 0 0 var(--shadow-size) var(--shadow);
  border: var(--border-thickness) solid var(--text);
  overflow: hidden;
}

.item.nsfw::after {
  --size: calc(1/4 * var(--image-size));
  content: url(18_plus_white.svg);
  height: var(--size);
  width: var(--size);

  display: inline-block;
  position: absolute;
  top: 3px;
  right: 3px;

  transform: rotate(30deg);
  mix-blend-mode: multiply;
}

figure {
  margin: 0;
  padding: 0;
}

.item figcaption {
  width: 100%;
  margin: 0;
  padding: var(--border-thickness);

  box-sizing: border-box;
  position: absolute;
  left: 0;
  bottom: 0;

  font-size: 80%;
  font-weight: 500;
  text-align: center;

  background: hsla(47, 74%, 89%, 87%);
  text-shadow:
    -1px -1px 1px hsla(47, 74%, 89%, 87%),
     1px -1px 1px hsla(47, 74%, 89%, 87%),
    -1px  1px 1px hsla(47, 74%, 89%, 87%),
     1px  1px 1px hsla(47, 74%, 89%, 87%);
  border-top: 2px solid var(--text);
}

.year-marker {
  background: var(--text);
  display: flex;
  justify-content: center;
  align-items: center;
  grid-area: auto / 1 / auto / auto;
}

.year-text {
  color: var(--lighter-tum);
  transform: rotate(-45deg);
  font-weight: 900;
  font-size: 300%;
}


@media (hover) {
  .item:not(.year-marker):hover {
    --shadow-size: 20px;
  }

  .item:hover figcaption {
    opacity: 20%;
  }

  @media (prefers-reduced-motion) {
    .item:hover figcaption {
      transform: translateY(80%);
    }
  }

  @media (prefers-reduced-motion: no-preference) {
    .item:hover img {
      filter: contrast(120%);
    }

    .item:hover figcaption {
      transform: translate(-20%, 80%) rotateZ(7deg);
    }

    .item, .item figcaption, .item img {
      transition: all 0.2s ease-in-out;
    }
  }
}

@media (hover: none) {
  .item:not(.year-marker) {
    height: auto;
  }

  .item a {
    display: block;
    margin: 0;
    height: var(--image-size);
  }

  .item img {
    margin-bottom: 0;
  }

  .item figcaption {
    position: static;
    background: hsl(0, 0%, 100%, 50%);
  }
}

@media (prefers-reduced-transparency) {
  .item figcaption {
    background: hsl(47, 74%, 89%);
    text-shadow: none;
  }

  .item:hover figcaption {
    opacity: 100%;
  }

  figcaption {
    transition: none;
  }
}