use 100vh instead of flip flopping between the two - works on all suported browsers

app/assets/stylesheets/framework/layout.scss

@@ -130,9 +130,7 @@ of the body element here, we negate cascading side effects but allow momentum sc
 }
 
 .vertical-center {
-  min-height: 100%;
   min-height: 100vh;
-
   display: flex;
   align-items: center;
 }