diff --git a/Userland/Libraries/LibWeb/CSS/Identifiers.json b/Userland/Libraries/LibWeb/CSS/Identifiers.json
index fdd0ee5a09..15238673b1 100644
--- a/Userland/Libraries/LibWeb/CSS/Identifiers.json
+++ b/Userland/Libraries/LibWeb/CSS/Identifiers.json
@@ -122,6 +122,7 @@
   "lower-alpha",
   "lower-latin",
   "lower-roman",
+  "ltr",
   "medium",
   "middle",
   "monospace",
@@ -157,10 +158,12 @@
   "row",
   "row-resize",
   "row-reverse",
+  "rtl",
   "sans-serif",
   "scroll",
-  "serif",
   "se-resize",
+  "separate",
+  "serif",
   "small",
   "smaller",
   "solid",