_includes/head.html

<head>
  <meta charset="utf-8" />
  <meta name="viewport" content="width=device-width, initial-scale=1" />
  <title>{% if page.title %}{{ page.title | escape }}{% else %}{{ site.title | escape }}{% endif %}</title>
  <meta name="description" content="{% if page.excerpt %}{{ page.excerpt | strip_html | strip_newlines | truncate: 160 }}{% else %}{{ site.description }}{% endif %}">
  <!--[if lte IE 8]><script src="{{ "/js/ie/html5shiv.js" | prepend: site.baseurl }}"></script><![endif]-->
  <link rel="canonical" href="{{ page.url | replace:'index.html','' | prepend: site.baseurl | prepend: site.url }}">
  <link rel="stylesheet" href="{{ "/css/main.css" | prepend: site.baseurl }}" />
  <!--[if lte IE 8]><link rel="stylesheet" href="{{ "/css/ie8.css" | prepend: site.baseurl }}" /><![endif]-->
  <!--[if lte IE 9]><link rel="stylesheet" href="{{ "/css/ie9.css" | prepend: site.baseurl }}" /><![endif]-->
  <link rel="alternate" type="application/rss+xml" title="{{ site.title }}" href="{{ "/feed.xml" | prepend: site.baseurl | prepend: site.url }}">
  <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','https://www.google-analytics.com/analytics.js','ga');
  ga('create', '{{ site.google_analytics }}', 'auto');
  ga('send', 'pageview');
  </script>
</head>