CSS 如何实现 Modal 弹窗？

Question

CSS 如何实现 Modal 弹窗？

仓乃文 · Accepted Answer

Modal 弹窗通过 :target 伪类实现纯 CSS 的弹窗打开/关闭，无需 JavaScript 控制显示状态。

```css
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s;
}

.modal-overlay:target {
  opacity: 1;
  visibility: visible;
}

.modal-content {
  background: #fff;
  border-radius: 8px;
  padding: 30px;
  max-width: 500px;
  width: 90%;
  transform: translateY(-20px);
  transition: transform 0.3s;
}

.modal-overlay:target .modal-content {
  transform: translateY(0);
}

.modal-close {
  position: absolute;
  top: 10px;
  right: 15px;
  font-size: 24px;
  text-decoration: none;
  color: #999;
}
```

补充说明：
- :target 匹配 URL hash 对应的元素 ID
- 点击关闭按钮（href="#"）清除 hash，弹窗关闭
- 遮罩层覆盖全屏，点击遮罩空白区域也可关闭
- 适合确认对话框、图片预览、表单弹窗等场景