diff --git a/resources/servo.css b/resources/servo.css
index c1dbe1c1ddc..98ee52c0982 100644
--- a/resources/servo.css
+++ b/resources/servo.css
@@ -132,7 +132,7 @@ textarea {
   -servo-overflow-clip-box: content-box;
 }
 
-// https://html.spec.whatwg.org/multipage/rendering.html#the-details-and-summary-elements
+/* https://html.spec.whatwg.org/multipage/rendering.html#the-details-and-summary-elements */
 details {
   display: block;
 }