diff --git a/components/style/values/generics/font.rs b/components/style/values/generics/font.rs
index 59907ff7920..d622026ff60 100644
--- a/components/style/values/generics/font.rs
+++ b/components/style/values/generics/font.rs
@@ -255,7 +255,7 @@ pub enum KeywordSize {
     XXLarge,
     // This is not a real font keyword and will not parse
     // HTML font-size 7 corresponds to this value
-    #[css(skip)]
+    #[css(keyword = "xxx-large")]
     XXXLarge,
 }