demo/templates/base.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Schema.org Content Checker (work-in-progress)</title>

    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/noty/3.1.4/noty.css">
    <link rel="stylesheet" href="{{ url_for('static', filename='css/libs/bootstrap.min.css')[1:] }}">
    <link rel="stylesheet" href="{{ url_for('static', filename='css/master.css')[1:] }}">
    {% block styles %}
    {% endblock %}
</head>
<body>

<div class="header">
    <div class="title">Schema.org Content Checker (work-in-progress)</div>
    <div class="d-flex">
        {% block header_controls %}
        {% endblock %}
    </div>
</div>

{% block content %}
{% endblock %}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<!-- Noty - for pretty notifications -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/noty/3.1.4/noty.min.js"></script>
{% block scripts %}
{% endblock %}
</body>
</html>