如何用纯CSS和HTML覆盖图像/水印

<div class="image-container">
  <img src="image.jpg" alt="Image">
</div>

.image-container {
  position: relative;
}

.image-container::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5); /* 设置覆盖元素的背景颜色和透明度 */
  z-index: 1; /* 设置层叠顺序，使覆盖元素在图像上方 */
}

.image-container::after {
  /* ... */
  z-index: 1;
}

.image-container::before {
  content: "Watermark";
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 24px;
  color: white;
  z-index: 2; /* 设置层叠顺序，使水印在覆盖元素上方 */
}