diff --git a/frontend/src/demo.html b/frontend/src/demo.html
index b82d162..2c23827 100644
--- a/frontend/src/demo.html
+++ b/frontend/src/demo.html
@@ -3,10 +3,14 @@
   <head>
     <meta charset="utf-8" />
     <style>
-        body { padding: 0; }
+        body {
+            background: black;
+            padding: 0;
+            margin: 0;
+        }
         iframe {
-            width: 100%;
-            height: 100%;
+            width: 100vw;
+            height: 100vh;
             border: 0;
         }
     </style>
