popup.html

<html>
  <head>
    <style>
    p,a {
      word-break: break-word;
      word-wrap: break-word;
    }
  </style>
</head>
  <body>
    <div style="width: 300px">
      <p>
        The extension activates by default. To disable it, navigate to the extension center and switch the toggle off. View the course dependency graph at:  <a href="https://web.cs.dartmouth.edu/undergraduate/courses#course-dag">https://web.cs.dartmouth.edu/undergraduate/courses#course-dag</a>.
      </p>
    </div>
  </body>
</html>