add _old-ios.scss

src/client/styles/scss/_old-ios.scss

@@ -0,0 +1,9 @@
+body.grw-old-ios:not(.on-edit) {
+  .grw-navbar {
+    position: initial !important;
+    top: 0 !important;
+  }
+  .grw-subnav-fixed-container {
+    top: 0 !important;
+  }
+}

src/client/styles/scss/style-app.scss

@@ -46,6 +46,7 @@
 @import 'mirror_mode';
 @import 'modal';
 @import 'navbar';
+@import 'old-ios';
 @import 'on-edit';
 @import 'page-duplicate-modal';
 @import 'page_list';