diff --git a/spec/05-classes-and-objects.md b/spec/05-classes-and-objects.md
index cff54426413d..3a70f2a1370c 100644
--- a/spec/05-classes-and-objects.md
+++ b/spec/05-classes-and-objects.md
@@ -964,7 +964,7 @@ This form of extensibility can be excluded by declaring the base class
 directly extend `Expr` must be in the same source file as
 `Expr`.
 
-### Traits
+## Traits
 
 ```ebnf
 TmplDef          ::=  `trait' TraitDef