feat(auth): update layout and styling for login and registration pages

app/(auth)/login/page.tsx

@@ -3,12 +3,11 @@ import { LoginForm } from "@/components/auth/login-form";
 
 export default function LoginPage() {
   return (
-    <main className="mx-auto flex min-h-screen w-full max-w-md flex-col justify-center px-6 py-16">
-      <div className="rounded-xl border border-border/80 bg-panel/50 p-6 md:p-7">
-        <div className="mb-8 space-y-3">
+    <main className="auth-shell">
+      <div className="w-full p-2 md:p-4">
+        <div className="mb-8 space-y-3 text-center">
           <p className="text-xs uppercase tracking-[0.2em] text-muted">PayMe</p>
-          <h1 className="text-2xl font-semibold">Sign in</h1>
-          <p className="text-sm text-muted">Use your email and password to manage your public payment profile.</p>
+          <h1 className="text-3xl font-semibold">Sign in</h1>
         </div>
         <LoginForm />
         <p className="mt-6 text-sm text-muted">