body {
  background: #f6f7f9;
}

/* 相册封面 */
.album-card {
  overflow: hidden;
  transition: transform .15s ease, box-shadow .15s ease;
}
.album-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 .5rem 1rem rgba(0,0,0,.12);
}
.album-cover {
  height: 160px;
  object-fit: cover;
  width: 100%;
}
.album-cover-empty {
  height: 160px;
  background: #e9ecef;
  font-size: .9rem;
}

/* 瀑布流网格 */
.masonry {
  column-count: 2;
  column-gap: .75rem;
}
@media (min-width: 768px) { .masonry { column-count: 3; } }
@media (min-width: 992px) { .masonry { column-count: 4; } }
@media (min-width: 1400px) { .masonry { column-count: 5; } }

.masonry-item {
  display: block;
  margin-bottom: .75rem;
  break-inside: avoid;
}
.masonry-item img {
  width: 100%;
  border-radius: .5rem;
  transition: opacity .15s ease;
}
.masonry-item:hover img {
  opacity: .85;
}

/* 拖拽上传区 */
.dropzone {
  border: 2px dashed #adb5bd;
  border-radius: .75rem;
  padding: 2.5rem 1rem;
  text-align: center;
  cursor: pointer;
  background: #fff;
  transition: border-color .15s ease, background .15s ease;
}
.dropzone.dragover {
  border-color: #0d6efd;
  background: #eef4ff;
}