diff --git a/components/style/values/specified/box.rs b/components/style/values/specified/box.rs
index 1289fc6eaa8..3a6677de42a 100644
--- a/components/style/values/specified/box.rs
+++ b/components/style/values/specified/box.rs
@@ -1911,10 +1911,6 @@ pub enum Appearance {
     MozMacSourceList,
     #[parse(condition = "ParserContext::in_ua_or_chrome_sheet")]
     MozMacSourceListSelection,
-    #[parse(condition = "ParserContext::in_ua_or_chrome_sheet")]
-    MozMacVibrantTitlebarDark,
-    #[parse(condition = "ParserContext::in_ua_or_chrome_sheet")]
-    MozMacVibrantTitlebarLight,
 
     /// A themed focus outline (for outline:auto).
     ///
diff --git a/components/style/values/specified/color.rs b/components/style/values/specified/color.rs
index 82805bf1efa..f751ede9a2e 100644
--- a/components/style/values/specified/color.rs
+++ b/components/style/values/specified/color.rs
@@ -434,10 +434,6 @@ pub enum SystemColor {
     /// Inactive light hightlight
     MozMacSecondaryhighlight,
 
-    /// Font smoothing background colors needed by the Mac OS X theme, based on
-    /// -moz-appearance names.
-    MozMacVibrantTitlebarLight,
-    MozMacVibrantTitlebarDark,
     MozMacMenupopup,
     MozMacMenuitem,
     MozMacActiveMenuitem,