diff --git a/engine/layout.js b/engine/layout.js
index 3b4bc59..45b9482 100644
--- a/engine/layout.js
+++ b/engine/layout.js
@@ -541,6 +541,7 @@ export class LayoutNode extends Node {
     }
 
     val = parseFloat(val);
+    if (Number.isNaN(val)) val = 0;
 
     switch (unit) {
       case 'px': return val;