diff --git a/app/models/design/theme.rb b/app/models/design/theme.rb
index 61a621c0..0935fe12 100644
--- a/app/models/design/theme.rb
+++ b/app/models/design/theme.rb
@@ -1,6 +1,6 @@
 class Theme < Stylesheet
   
-  belongs_to :css, polymorphic: true
+  belongs_to :design
   
   protected