diff --git a/app/assets/javascripts/discourse/templates/application.hbs b/app/assets/javascripts/discourse/templates/application.hbs
index b5ff68ac9..6b9b13321 100644
--- a/app/assets/javascripts/discourse/templates/application.hbs
+++ b/app/assets/javascripts/discourse/templates/application.hbs
@@ -1,6 +1,6 @@
 {{render "header"}}
 
-<div id='main-outlet' {{bind-attr class=backgroundClass}}>
+<div id='main-outlet'>
   {{outlet}}
   {{render "user-card"}}
 </div>
diff --git a/lib/sass/discourse_sass_importer.rb b/lib/sass/discourse_sass_importer.rb
index 26721cdbb..ce16a8073 100644
--- a/lib/sass/discourse_sass_importer.rb
+++ b/lib/sass/discourse_sass_importer.rb
@@ -50,7 +50,7 @@ class DiscourseSassImporter < Sass::Importers::Filesystem
       contents = ""
       Category.where('background_url IS NOT NULL').each do |c|
         if c.background_url.present?
-          contents << "body.category-#{c.id} { background-image: url(#{c.background_url}) }\n"
+          contents << "body.category-#{c.slug} { background-image: url(#{c.background_url}) }\n"
         end
       end
       return Sass::Engine.new(contents, options.merge(