{% extends "cms_default.html" %}
{% load cms_tags %}

{% block body %}
<div>
  <nav id='outer-nav'>
    {% static_placeholder "sitewide sidebar" %}
    {% placeholder "sidebar" inherit %}
    <nav id="side-nav">
      {% include 'includes/sidebar.html' %}
    </nav>
  </nav>
  <article>
    {% placeholder "main" %}
  </article>
</div>
{% endblock %}

{% extends "cms_default.html" %}
{% load cms_tags %}

{% block body %}
<div>
  <nav id='outer-nav'>
    <nav id="side-nav">
      {% include 'includes/sidebar.html' %}
    </nav>
    {% static_placeholder "sitewide sidebar" %}
    {% placeholder "sidebar" inherit %}
  </nav>
  <article>
    {% placeholder "main" %}
  </article>
</div>
{% endblock %}

Move custom sidebar below navigation
Move custom sidebar below navigation
