diff --git a/components/style/values/generics/length.rs b/components/style/values/generics/length.rs
index 97e9712eabc..3885220efa5 100644
--- a/components/style/values/generics/length.rs
+++ b/components/style/values/generics/length.rs
@@ -161,6 +161,7 @@ pub enum GenericSize<LengthPercent> {
     #[cfg(feature = "gecko")]
     #[animation(error)]
     MozAvailable,
+    #[cfg(feature = "gecko")]
     #[animation(error)]
     #[css(function = "fit-content")]
     FitContentFunction(LengthPercent)
@@ -218,6 +219,7 @@ pub enum GenericMaxSize<LengthPercent> {
     #[cfg(feature = "gecko")]
     #[animation(error)]
     MozAvailable,
+    #[cfg(feature = "gecko")]
     #[animation(error)]
     #[css(function = "fit-content")]
     FitContentFunction(LengthPercent),
diff --git a/components/style/values/specified/length.rs b/components/style/values/specified/length.rs
index 03189e28caf..e73a9ddfde0 100644
--- a/components/style/values/specified/length.rs
+++ b/components/style/values/specified/length.rs
@@ -1251,11 +1251,8 @@ macro_rules! parse_size_non_length {
 fn is_fit_content_function_enabled() -> bool {
     static_prefs::pref!("layout.css.fit-content-function.enabled")
 }
-#[cfg(feature = "servo")]
-fn is_fit_content_function_enabled() -> bool {
-    false
-}
 
+#[cfg(feature = "gecko")]
 macro_rules! parse_fit_content_function {
     ($size:ident, $input:expr, $context:expr, $allow_quirks:expr) => {
         if is_fit_content_function_enabled() {
@@ -1279,6 +1276,7 @@ impl Size {
         allow_quirks: AllowQuirks,
     ) -> Result<Self, ParseError<'i>> {
         parse_size_non_length!(Size, input, "auto" => Auto);
+        #[cfg(feature = "gecko")]
         parse_fit_content_function!(Size, input, context, allow_quirks);
 
         let length = NonNegativeLengthPercentage::parse_quirky(context, input, allow_quirks)?;
@@ -1312,6 +1310,7 @@ impl MaxSize {
         allow_quirks: AllowQuirks,
     ) -> Result<Self, ParseError<'i>> {
         parse_size_non_length!(MaxSize, input, "none" => None);
+        #[cfg(feature = "gecko")]
         parse_fit_content_function!(MaxSize, input, context, allow_quirks);
 
         let length = NonNegativeLengthPercentage::parse_quirky(context, input, allow_quirks)?;