Adding template tag to render microsite css_overrides_file

common/djangoapps/microsite_configuration/templatetags/microsite.py

@@ -42,9 +42,22 @@ def platform_name():
 
 
 @register.simple_tag(name="favicon_path")
-def favicon_path(default=settings.FAVICON_PATH):
+def favicon_path(default=getattr(settings,'FAVICON_PATH', 'images/favicon.ico')):
     """
     Django template tag that outputs the configured favicon:
     {% favicon_path %}
     """
     return static(microsite.get_value('favicon_path', default))
+
+
+@register.simple_tag(name="microsite_css_overrides_file")
+def microsite_css_overrides_file():
+    """
+    Django template tag that outputs the css import for a:
+    {% microsite_css_overrides_file %}
+    """
+    file_path = microsite.get_value('css_overrides_file', None)
+    if file_path is not None:
+        return "<link href='{}' rel='stylesheet' type='text/css'>".format(static(file_path))
+    else:
+        return ""

lms/templates/main_django.html

@@ -20,6 +20,7 @@
   {% block headextra %}{% endblock %}
   {% render_block "css" %}
 
+  {% microsite_css_overrides_file %}
 
   <!--[if lt IE 9]>
   <script src="{% static 'js/html5shiv.js' %}"></script>