box-sizing added to init.html CSS (#21916)

resources/frontend_client/init.html

@@ -6,10 +6,19 @@
 
     <style media="screen">
       * {
-        padding: 0;
-        margin: 0;
+        box-sizing: border-box;
         font-family: Lato, 'Helvetica Neue', Helvetica, sans-serif;
+        margin: 0;
+        padding: 0;
       }
+
+      html,
+      body {
+        height: 100%;
+        min-height: 100%;
+        position: relative;
+      }
+
       progress[value] {
         -webkit-appearance: none;
         appearance: none;