_layouts/default.html

<!DOCTYPE html>
<html lang="en">
<head>
    <title>{{ page.title }}</title>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no">
    <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Open+Sans:200,300,400,600,700">
    <link rel="stylesheet" 
        href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" 
        integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" 
        crossorigin="anonymous">
    <link rel="stylesheet" href="/static/css/main.css">
</head>
<body id="{{ page.id }}">

    {% include header.html %}
    
    {{ content }}

    {% include footer.html %}

</body>
</html>