Add max-scale

src/index.html

@@ -4,7 +4,7 @@
   <meta charset="utf-8">
   <meta http-equiv="X-UA-Compatible" content="IE=edge">
   <meta name="description" content="A responsive, interactive Audience Response System, developed at THM">
-  <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=2.0">
   <title>ARSnova</title>
 
   <base href="/">