Make the docs site basically responsive, by using flexbox instead of floats for the sidebar and allowing it to take up 100% width when the screen width is less than 480px

docs/source/_templates/localtoc.html

@@ -8,6 +8,6 @@
     :license: BSD, see LICENSE for details.
 #}
 {%- if display_toc %}
-<p><h3><a href="{{ pathto(master_doc) }}">{{ _('Table of Contents') }}</a></h3>
+<h3><a href="{{ pathto(master_doc) }}">{{ _('Table of Contents') }}</a></h3>
   {{ toc }}
 {%- endif %}