.book-card {
  overflow: hidden;
}

.book-cover {
  width: 100%;
  aspect-ratio: 2 / 3;
  object-fit: cover;
  transition: transform .4s ease;
}

.book-card:hover .book-cover {
  transform: scale(1.05);
}

.gallery-thumb-btn { cursor: pointer; }

.gallery-thumb {
  width: 100%;
  aspect-ratio: 4 / 3;           /* big thumbnails */
  overflow: hidden;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,.12);
  background: #0b0c10;
  box-shadow: 0 10px 24px rgba(0,0,0,.25);
}

.gallery-thumb img {
  object-fit: cover;
  transition: transform .35s ease;
  display: block;
}

.gallery-thumb-btn:hover .gallery-thumb img {
  transform: scale(1.05);
}