      <!-- Your HTML code here -->
      <html>
      <head>
        <style>
          /* Your CSS code here */
          body {
            background-color: #f2f2f2;
          }
          h1 {
            color: red;
          }
        </style>
      </head>
      <body>
        <h1>Hello, CodeMirror!</h1>
        <script>
          // Your JavaScript code here
          var message = "Hello from JavaScript!";
          console.log(message);
        </script>
      </body>
      </html>