.image-container {
  position: relative;
  width: 100%; /* 图片容器宽度自适应 */
}
.image-container img {
  border-radius: 8px;
}
.placeholder {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border-radius: 8px;
}

img {
  width: 100%;
  height: auto;
  display: block;
}