_layouts/default.html

<!DOCTYPE html>
<!--[if lt IE 7 ]><html class="ie ie6" lang="en"> <![endif]-->
<!--[if IE 7 ]><html class="ie ie7" lang="en"> <![endif]-->
<!--[if IE 8 ]><html class="ie ie8" lang="en"> <![endif]-->
<!--[if (gte IE 9)|!(IE)]><!--><html lang="en"> <!--<![endif]-->
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>{{ site.data.theme.name }} - {{ page.title }}</title>
  <meta name="author" content="{{ site.data.theme.name }}" />
  <meta name="description" content="The blog of {{ site.data.theme.name }}" />
  <link rel="canonical" href="{{ site.url }}{{ page.url | replace:'index.html','' }}" />

  <link href="//fonts.googleapis.com/css?family=Open+Sans:600,800" rel="stylesheet" type="text/css">
  <link rel="shortcut icon" href="/favicon.png">
  <link rel="alternate" type="application/atom+xml" title="{{ site.data.theme.name }}" href="{{site.url}}/atom.xml" />

  <link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.4.0/css/font-awesome.min.css" rel="stylesheet" integrity="sha256-k2/8zcNbxVIh5mnQ52A0r3a6jAgMGxFJFE2707UxGCk= sha512-ZV9KawG2Legkwp3nAlxLIVFudTauWuBpC10uEafMHYL0Sarrz5A7G79kXh5+5+woxQ5HM559XX2UZjMJ36Wplg==" crossorigin="anonymous">

  <link rel="stylesheet" href="/assets/css/all.css">
  <link rel="stylesheet" href="https://cdn.rawgit.com/knsv/mermaid/7.0.0/dist/mermaid.css">
  <script src="https://cdn.rawgit.com/knsv/mermaid/7.0.0/dist/mermaid.min.js"></script>
  <script>mermaid.initialize({startOnLoad: true;});</script>
</head>
<body>
  <div class="mermaid">
    graph TD;
        A-->B;
        A-->C;
        B-->D;
        C-->D;
  </div>
  <h1>Foo</h1>


  <div class="container">
    <div class="four columns sidebar">
      {% include sidebar.html %}
    </div>

    <div class="eleven columns content">
      {{ content }}

      <div class="footer">
        {% include footer.html %}
      </div>
    </div>
  </div>

{% include analytics.html %}
</body>
</html>