xxxxxxxxxx<html> <head> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="//cdn.bootcss.com/bootstrap/3.3.6/css/bootstrap.min.css"> <script src="//cdn.bootcss.com/jquery/2.1.1/jquery.min.js"></script> <script src="//cdn.bootcss.com/bootstrap/3.3.6/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <h2>背景</h2> <p class="bg-warning">该段落使用了类 "bg-warning"。</p> <a class="bg-warning" href="/index">该链接使用了类 "bg-warning"。</a> </div> </body></html>