diff --git a/.themes/classic/source/_layouts/default.html b/.themes/classic/source/_layouts/default.html
index 0b1fc3a..f670e1c 100644
--- a/.themes/classic/source/_layouts/default.html
+++ b/.themes/classic/source/_layouts/default.html
@@ -1,6 +1,6 @@
 {% capture root_url %}{{ site.root | strip_slash }}{% endcapture %}
 {% include head.html %}
-<body {% if page.body_id %} id="{{ page.body_id }}" {% endif %} {% if page.sidebar == false %} class="no-sidebar" {% endif %} {% if page.sidebar == 'collapse' %} class="collapse-sidebar sidebar-footer" {% endif %}>
+<body {% if page.body_id %} id="{{ page.body_id }}" {% endif %} {% if page.sidebar == false %} class="no-sidebar" {% endif %} {% if page.sidebar == 'collapse' or site.sidebar == 'collapse' %} class="collapse-sidebar sidebar-footer" {% endif %}>
   <header role="banner">{% include header.html %}</header>
   <nav role="navigation">{% include navigation.html %}</nav>
   <div id="main">
