drop the css one level deeper

settings.py

@@ -340,7 +340,7 @@ STANDALONE_DOMAINS = [
 MINIFY_BUNDLES = {
     'css': {
         # CSS files common to the entire site.
-        'common': (
+        'zamboni/css': (
             'css/legacy/main.css',
             'css/legacy/main-mozilla.css',
             'css/legacy/jquery-lightbox.css',

templates/base.html

@@ -15,7 +15,7 @@
           href="{{ url('amo.opensearch') }}" />
 
     {% block site_css %}
-      {{ css('common') }}
+      {{ css('zamboni/css') }}
       <!--[if IE]><link rel="stylesheet" href="{{ MEDIA_URL }}css/legacy/ie.css"><![endif]-->
       <!--[if IE 7]><link rel="stylesheet" href="{{ MEDIA_URL }}css/legacy/ie7.css"><![endif]-->
     {% endblock %}