Try minimum-scale instead of initial-scale.

vaibhavsagar · vaibhavsagar · commit 4ae2463e05b4 · 2016-10-02T20:03:00.000-04:00
diff --git a/app.py b/app.py
@@ -25,7 +25,7 @@
 <html>
 <head>
   <meta charset="utf-8">
-  <meta name="viewport" content="height=1920, width=1080, initial-scale=1">
+  <meta name="viewport" content="height=1920, width=1080, minimum-scale=1">
   <style type="text/css">
     body, iframe#main {{
       margin: 0;
