diff --git a/style/values/specified/text.rs b/style/values/specified/text.rs
index b68b1fdb7..fac251e6b 100644
--- a/style/values/specified/text.rs
+++ b/style/values/specified/text.rs
@@ -278,6 +278,7 @@ pub enum TextTransformCase {
     /// Capitalize each word.
     Capitalize,
     /// Automatic italicization of math variables.
+    #[cfg(feature = "gecko")]
     MathAuto,
 }