diff --git a/gtk/gtkcsstypesprivate.h b/gtk/gtkcsstypesprivate.h
index 2384280d8c..c0c884861a 100644
--- a/gtk/gtkcsstypesprivate.h
+++ b/gtk/gtkcsstypesprivate.h
@@ -24,6 +24,12 @@
 
 G_BEGIN_DECLS
 
+typedef enum {
+  GTK_CSS_INHERIT,
+  GTK_CSS_INITIAL,
+  GTK_CSS_CURRENT_COLOR
+} GtkCssSpecialValue;
+
 typedef enum {
   GTK_CSS_BACKGROUND_REPEAT_STYLE_NONE,
   GTK_CSS_BACKGROUND_REPEAT_STYLE_REPEAT,