diff --git a/doc-src/lib/default.rb b/doc-src/lib/default.rb
index 4a07e045..53f41de1 100644
--- a/doc-src/lib/default.rb
+++ b/doc-src/lib/default.rb
@@ -8,7 +8,11 @@ def body_class(item)
 end
 
 def body_id(item)
-  item.identifier.chop[1..-1].gsub(/\/|_/, "-")
+  if id = item.identifier.chop[1..-1]
+    id.gsub(/\/|_/, "-")
+  else
+    nil
+  end
 end
 
 def body_attributes(item)
diff --git a/doc-src/lib/stylesheets/sass_extensions.rb b/doc-src/lib/stylesheets/sass_extensions.rb
index 3fc9132a..5710402e 100644
--- a/doc-src/lib/stylesheets/sass_extensions.rb
+++ b/doc-src/lib/stylesheets/sass_extensions.rb
@@ -1,3 +1,4 @@
+require 'sass'
 module Sass
   module Tree
     class VariableNode < Node