代码示例:(标识:bs_txt_mark)
<!DOCTYPE html>
<html lang="en">
<head>
  <title>Bootstrap 实例</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link href="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.1.2/css/bootstrap.min.css" rel="stylesheet">
  <script src="https://cdn.bootcdn.net/ajax/libs/twitter-bootstrap/5.1.2/js/bootstrap.min.js"></script>
</head>
<body>

<div class="container mt-3">
  <h1>突出显示文本</h1>    
  <p>使用 mark 元素(或 .mark 类)来 <mark>突出显示</mark> 文本。</p>
</div>

</body>
</html>
运行结果: