{% if site.google_analytics %}
  {% assign prefix = site.google_analytics | slice: 0, 2 %}
  {% if prefix == "G-" %}
    <!-- Global site tag (gtag.js) - Google Analytics -->
    <script async src="https://www.googletagmanager.com/gtag/js?id={{ site.google_analytics }}"></script>
    <script>
      window.dataLayer = window.dataLayer || [];
      function gtag(){dataLayer.push(arguments);}
      gtag('js', new Date());

      gtag('config', '{{ site.google_analytics }}');
    </script>
  {% else %}
    <!-- Google Analytics -->
    <script>
      (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
      (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
      m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
      })(window,document,'script','//www.google-analytics.com/analytics.js','ga');

      ga('create', '{{ site.google_analytics }}', 'auto');
      ga('send', 'pageview');
    </script>
  {% endif %}
{% endif %}