@charset "UTF-8";
.helper-image {
  width: 100%;
  height: 100%;
  position: relative;
}
.helper-image img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: contain;
}
.helper-image-loading {
  display: none;
}

/* 交叉淡入：新旧 img 同时存在时叠加 */
.helper-image-transition-enter-active,
.helper-image-transition-leave-active {
  transition: opacity 0.3s ease-in-out;
}

/* 离开的旧图：absolute 叠在下方，淡出 */
.helper-image-transition-leave-active {
  position: absolute;
  inset: 0;
  z-index: 0;
}

/* 进入的新图：保持正常流，叠在上方 */
.helper-image-transition-enter-active {
  position: relative;
  z-index: 1;
}
.helper-image-transition-enter-from,
.helper-image-transition-leave-to {
  opacity: 0;
}