html鼠标悬停时出现下划线应该怎么设置

鼠标悬停时出现下划线应该怎么设置？

:hover鼠标悬停，border-bottom下边框

img

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .text:hover {
      border-bottom: 1px solid #666;
    }
  </style>
</head>
<body>
  <span class="text">html鼠标悬停时出现下划线</span>
</body>
</html>

官方的：

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>悬停添加下划线</title>
    <style>
        .box:hover {
            text-decoration: underline;
        }
    </style>
</head>

<body>
    <span class="box">html鼠标悬停时出现下划线</span>
</body>

</html>