title: How can I customise flask-admin to add it to a sb-admin themed app
body: <p>I have an existing application that I want to add flask-admin too and retain the same look and feel in the admin interface.
  Ideally I'd have the admin interface retain the side menu from the bootstrap4 theme I am using (sb-admin-2). However, I can't figure out how to do that.</p>
  <p>I would at least like to format the page a little nicer so looking at the flask-admin documentation there is this sentence:</p>
  <pre><code>Customize the look by specifying a Bootswatch theme that suits your needs (see http://bootswatch.com/3/ for available swatches).
  </code></pre>
  <p>But no information on how to do this. Can someone point me in the right direction to either embed the admin pages in my current app (preferable) which is just a bootstrap4 theme, or add some other custom theme from bootswatch?</p>
  <p>I tried creating a html file in templates/admin to override master.html with this to no effect:</p>
  <pre><code>{% extends admin_base_template %}
  
  {% block head_css %}
    {{ super() }}
    &lt;link rel=&quot;stylesheet&quot; href=&quot;{{ url_for('static', filename='css/sb-admin-2.css') }}&quot;&gt;
  {% endblock %}
  </code></pre>