Flask html template with bootstrap formatting

account.html

{% extends "base.html" %}
{% block content %}
<div class="jumbotron">
    <div align='center'>
        <h1>Welcome to the page for {{ current_user.username }}</h1>
        <img align="center" src="{{ url_for('static', filename='profile_pics/'+current_user.profile_image) }}">
    </div>
</div>
<div class="container">
    <form method="POST">
        {{ form.hidden_tag() }}
        <div class="form-group">
            {{ form.username.label(class='form-group') }} {{ form.username(class='form-control') }}
        </div>
        <div class="form-group">
            {{ form.email.label(class='form-group') }} {{ form.email(class='form-control') }}
        </div>
        <div class="form-group">
            {{ form.picture.label(class='form-group') }} {{ form.picture(class='form-control') }}
        </div>
        <div class="form-group">
            {{ form.submit(class="btn btn-primary") }}
        </div>
    </form>
</div>
{% endblock %}