browser_action.html

<html>
  <head>
    <title>Google Meet PTT</title>
    <script type="text/javascript" src="browser_action.js"></script>
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
    <link rel="stylesheet" href="style.css">
  </head>
  <body>
    <i class="fa fa-microphone" id="microphone"></i>
    
    <div class="center">
        <span style="width: 100%; display:inline-block; text-align: center">Press and hold "<label id="pttKey"></label>" or whatever key you set to talk!</span>
    </div>
  </body>
</html>