diff --git a/TODO b/TODO
index a4492d27..e77f6065 100644
--- a/TODO
+++ b/TODO
@@ -6,6 +6,7 @@ Testing:
 
 Documentation:
   Haml::Engine public method documentation could use work
+  !! Document at-rules.
 
 Features:
   Sass should throw generic errors for undefined constants, not syntax errors