<!DOCTYPE html>
<html lang="en-US">
  {% include head.html title=page.title %}
  <body>
    <main class="u-pad1 u-spaceItems1">
      {% include hero.html %}

      {{ content }}

      {% include footer.html %}
    </main>
    <script src="{{ site.github.url }}/js/main.js"></script>
    <script>
      if ('serviceWorker' in navigator) {
        navigator.serviceWorker.register('{{ site.github.url }}/sw.js');
      }
    </script>
  </body>
</html>

<!DOCTYPE html>
<html lang="en-US">
  {% include head.html title=page.title %}
  <body>
    <main class="u-pad1 u-spaceItems1">
      {% include hero.html %}

      {{ content }}
    </main>
    {% include footer.html %}
    <script src="{{ site.github.url }}/js/main.js"></script>
    <script>
      if ('serviceWorker' in navigator) {
        navigator.serviceWorker.register('{{ site.github.url }}/sw.js');
      }
    </script>
  </body>
</html>

Move footer include outside of <main>
Move footer include outside of <main>
