nomilo/templates/bases/app.html

{% extends "bases/base.html" %}

{% block content %}
    <nav aria-label="Principal" class="main">
        <ul>
            <li><a href="#">Account</a></li>
            <li><a href="#">Zones</a></li>
            <li><a href="#">Admin</a></li>
        </ul>
    </nav>
    <main>
        {% block main %}{% endblock main %}
    </main>
{% endblock content %}