index.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Spatial Navigation Demo</title>
  <style>
    html, body, div, span, applet, object, iframe,
    h1, h2, h3, h4, h5, h6, p, blockquote, pre,
    a, abbr, acronym, address, big, cite, code,
    del, dfn, em, img, ins, kbd, q, s, samp,
    small, strike, strong, sub, sup, tt, var,
    b, u, i, center,
    dl, dt, dd, ol, ul, li,
    fieldset, form, label, legend,
    table, caption, tbody, tfoot, thead, tr, th, td,
    article, aside, canvas, details, embed,
    figure, figcaption, footer, header, hgroup,
    menu, nav, output, ruby, section, summary,
    time, mark, audio, video {
      margin: 0;
      padding: 0;
      border: 0;
    }
  </style>
</head>
<body>
  <div id="root"></div>
</body>
</html>