e: light dark;
      }
      html, body {
        margin: 0;      /* remove default margin */
        height: 100%;   /* make body fill the browser window */
        display: flex;
        place-content: center center;
      }
      canvas {
        width: 600px;
        height: 600px;
        max-width: 100%;
        display: block;
      }
    </style>
    <script defer src="main.js" type="module"></script>
    <script defer type="module" src="../../js/iframe-helper.js"></script>
  </head>
  <body>
    <c