diff --git a/Libraries/LibWeb/CSS/Properties.json b/Libraries/LibWeb/CSS/Properties.json
index 083b184f07d..fe5de26f7ca 100644
--- a/Libraries/LibWeb/CSS/Properties.json
+++ b/Libraries/LibWeb/CSS/Properties.json
@@ -2723,7 +2723,8 @@
     "inherited": false,
     "initial": "none",
     "affects-layout": false,
-    "affects-stacking-context": true
+    "affects-stacking-context": true,
+    "percentages-resolve-to": "length"
   },
   "transform-box": {
     "animation-type": "discrete",