Fix reward code modal and mobile viewport dock

src/App.tsx

@@ -1,4 +1,11 @@
-import { lazy, Suspense, useCallback, useEffect, useRef, useState } from 'react';
+import {
+  lazy,
+  Suspense,
+  useCallback,
+  useEffect,
+  useRef,
+  useState,
+} from 'react';
 
 import { useAuthUi } from './components/auth/AuthUiContext';
 import { PlatformEntryFlowShell } from './components/platform-entry/PlatformEntryFlowShell';
@@ -133,7 +140,7 @@ export default function App() {
 
   return (
     <div
-      className={`platform-ui-shell platform-theme ${platformThemeClass} flex h-screen max-h-screen flex-col overflow-hidden bg-[image:var(--platform-body-fill)] p-2 font-sans text-[var(--platform-text-strong)] sm:p-4`}
+      className={`platform-ui-shell platform-viewport-shell platform-theme ${platformThemeClass} flex flex-col overflow-hidden bg-[image:var(--platform-body-fill)] p-2 font-sans text-[var(--platform-text-strong)] sm:p-4`}
     >
       <PlatformEntryFlowShell
         selectionStage={selectionStage}