2023-09-05T18:29:29.png

<!DOCTYPE html>
<html>
<head>
    <title>鼠标悬停显示/隐藏菜单</title>
    <style>
        .container {
            align-items: flex-start;
        }
        
        .subnav {
            position: relative; /* 添加相对定位 */
            width: 200px;
        }
        
  .subnav ul {
  display: none;
  position: fixed;
  top: 0;
  left: 111px;
  width: 300px; /* 调整宽度 */
  box-shadow: 0 1px 2px #222;
  list-style: none;
  padding: 0;
  /* 添加多列布局样式 */
  columns: 2;
  -webkit-columns: 2;
  -moz-columns: 2;
}

.subnav li {
  height: 40px;
  text-align: center;
  line-height: 40px;
  background: white;
  margin-right: 10px; /* 可选，用于设置列表项之间的间距 */

  /* 设置列宽度 */
  break-inside: avoid;
  -webkit-column-break-inside: avoid;
  -moz-column-break-inside: avoid;
}

        .subnav:hover ul {
            display: block;
        }
        
  
        
        .subnav li:hover {
            color: red;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="subnav">
            <a href="#">菜单按钮1</a>
            <ul>
                <li>菜单项1</li>
                <li>菜单项2</li>
                <li>菜单项3</li>
            </ul>
        </div>
      <br><br><br>
        <div class="subnav">
            <a href="#">菜单按钮2</a>
            <ul>
                <li>菜单项4</li>
                <li>菜单项5</li>
                <li>菜单项6</li>
            </ul>
        </div>
    </div>
</body>
</html>