diff --git a/fixtures/dom/src/style.css b/fixtures/dom/src/style.css
index 6d401295c8..f17ec79024 100644
--- a/fixtures/dom/src/style.css
+++ b/fixtures/dom/src/style.css
@@ -50,7 +50,7 @@ h3 {
   margin: 8px 0 16px;
 }
 
-h4, h4, h5, h6 {
+h4, h5, h6 {
   font-size: 16px;
   margin: 0 0 16px;
 }