&lt!DOCTYPE html>
&lthtml lang="en">
&lthead>
   &lttitle>{% block title %}My Site{% endblock %}
   {% block css %}
   {% endblock %}
   &ltmeta name="viewport" content="width=device-width, initial-scale=1.0">
  &lt/head>
 &ltbody>
 Hello, world!
 &lt/body>
 &lt/html>
