diff --git a/src/_includes/layouts/diffuse.vto b/src/_includes/layouts/diffuse.vto
index 070b5b21..bc916892 100644
--- a/src/_includes/layouts/diffuse.vto
+++ b/src/_includes/layouts/diffuse.vto
@@ -4,6 +4,7 @@ title: "Diffuse"
 base: "./"
 ---
 
+<!doctype html>
 <html lang="en">
   <head>
     <meta charset="UTF-8" />