_includes/head.html

<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <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="{{ page.excerpt | default: site.description | strip_html | normalize_whitespace | truncate: 160 | escape }}">

  <link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet" integrity="sha384-wvfXpqpZZVQGK6TAh5PVlGOfQNHSoD2xbE+QkPxCAFlNEevoEH3Sl0sibVcOQVnN" crossorigin="anonymous">
  <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
  <link rel="stylesheet" href="assets/main.css">
  <link rel="canonical" href="{{ page.url | replace:'index.html','' | absolute_url }}">
  <link rel="alternate" type="application/rss+xml" title="{{ site.title | escape }}" href="{{ "/feed.xml" | relative_url }}">

  {% if jekyll.environment == 'production' and site.google_analytics %}
  {% include google-analytics.html %}
  {% endif %}
</head>