graphPaname/app/templates/base.html

{% extends 'bootstrap/base.html' %}

{% block title %}
{% if title %}{{ title }} - graphPaname{% else %}graphPaname{% endif %}
{% endblock %}

{% block styles %}
<link rel="stylesheet"
      href="{{url_for('.static', filename='bootstrap.min.css')}}">
{% endblock %}

{% block navbar %}
<nav class="navbar navbar-expand-lg navbar-dark bg-primary">
    <a class="navbar-brand" href="{{ url_for('index') }}">graphPaname</a>
    <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarColor01" aria-controls="navbarColor01" aria-expanded="false" aria-label="Toggle navigation">
        <span class="navbar-toggler-icon"></span>
    </button>

    <div class="collapse navbar-collapse" id="navbarColor01">
        <ul class="navbar-nav mr-auto">
            <li class="nav-item active">
                <a class="nav-link" href="{{ url_for('index') }}">Home <span class="sr-only">(current)</span></a>
            </li>
            <li class="nav-link"><a href="{{ url_for('data') }}">Data</a></li>
            <li class="nav-link"><a href="{{ url_for('photos') }}">Photos</a></li>
        </ul>
    </div>
</nav>
{% endblock %}

{% block content %}
<div class="container">
    {# application content needs to be provided in the app_content block #}
    {% block app_content %}{% endblock %}
</div>
{% endblock %}