diff --git a/System/Libraries/Css/Tokenizer.HC b/System/Libraries/Css/Tokenizer.HC
index 4bb7e91..10547dc 100644
--- a/System/Libraries/Css/Tokenizer.HC
+++ b/System/Libraries/Css/Tokenizer.HC
@@ -3,6 +3,12 @@
 #define CSS_DISPLAY_INLINE 2
 #define CSS_DISPLAY_INLINE_BLOCK 3
 
+#define CSS_DISTANCE_UNDEFINED 0
+#define CSS_DISTANCE_PIXELS 1
+#define CSS_DISTANCE_EM 2
+#define CSS_DISTANCE_PERCENT 2
+#define CSS_DISTANCE_AUTO 3
+
 #define CSS_TEXT_ALIGN_LEFT 0
 #define CSS_TEXT_ALIGN_CENTER 1
 #define CSS_TEXT_ALIGN_RIGHT 2