diff --git a/app/Http/Controllers/Auth/GoogleController.php b/app/Http/Controllers/Auth/GoogleController.php
index 3bb85d0..f12e409 100644
--- a/app/Http/Controllers/Auth/GoogleController.php
+++ b/app/Http/Controllers/Auth/GoogleController.php
@@ -27,10 +27,13 @@ public function register()
     public function callback(Request $request)
     {
         try {
-            $googleUser = Socialite::driver('google')->user();
+            // Using stateless() prevents the InvalidStateException caused by 
+            // dropped cookies when routing through tunnels like Expose or Ngrok.
+            $googleUser = Socialite::driver('google')->stateless()->user();
         } catch (\Exception $e) {
+            \Log::error('Google Auth Failed: ' . $e->getMessage());
             return redirect()->route('login')->withErrors([
-                'email' => 'Google authentication was cancelled or failed. Please try again.',
+                'email' => 'Google authentication failed. Please try again.',
             ]);
         }
 
@@ -40,24 +43,22 @@ public function callback(Request $request)
             ->orWhere('email', $googleUser->getEmail())
             ->first();
 
-        if ($intent === 'register') {
-            if ($existingUser) {
-                return redirect()->route('login')->withErrors([
-                    'email' => 'An account with this email already exists. Please log in instead.',
+        if ($intent === 'login') {
+            if (!$existingUser) {
+                return redirect()->route('register')->withErrors([
+                    'email' => 'No account found with this Google account. Please register first.',
                 ]);
             }
 
-            $newUser = User::create([
-                'name' => $googleUser->getName(),
-                'email' => $googleUser->getEmail(),
+            $existingUser->update([
                 'google_id' => $googleUser->getId(),
                 'avatar' => $googleUser->getAvatar(),
-                'password' => Hash::make(Str::random(32)),
             ]);
 
-            Auth::login($newUser, true);
+            Auth::login($existingUser, true);
+            $request->session()->regenerate(); // CRITICAL: Persists the session state
             
-            return redirect()->route('dashboard');
+            return redirect()->intended(route('dashboard'));
         }
 
         if ($intent === 'register') {
@@ -73,12 +74,12 @@ public function callback(Request $request)
                 'google_id' => $googleUser->getId(),
                 'avatar' => $googleUser->getAvatar(),
                 'password' => Hash::make(Str::random(32)),
-                'api_token' => Str::random(60),
             ]);
 
             Auth::login($newUser, true);
+            $request->session()->regenerate(); // CRITICAL: Persists the session state
             
-            return redirect()->route('dashboard');
+            return redirect()->intended(route('dashboard'));
         }
 
         return redirect()->route('login');
diff --git a/app/Http/Requests/Auth/LoginRequest.php b/app/Http/Requests/Auth/LoginRequest.php
index 711e0a1..953b893 100644
--- a/app/Http/Requests/Auth/LoginRequest.php
+++ b/app/Http/Requests/Auth/LoginRequest.php
@@ -2,29 +2,24 @@
 
 namespace App\Http\Requests\Auth;
 
+use App\Models\User;
 use Illuminate\Auth\Events\Lockout;
 use Illuminate\Contracts\Validation\ValidationRule;
 use Illuminate\Foundation\Http\FormRequest;
 use Illuminate\Support\Facades\Auth;
+use Illuminate\Support\Facades\Hash;
 use Illuminate\Support\Facades\RateLimiter;
 use Illuminate\Support\Str;
 use Illuminate\Validation\ValidationException;
+use RuntimeException;
 
 class LoginRequest extends FormRequest
 {
-    /**
-     * Determine if the user is authorized to make this request.
-     */
     public function authorize(): bool
     {
         return true;
     }
 
-    /**
-     * Get the validation rules that apply to the request.
-     *
-     * @return array<string, ValidationRule|array<mixed>|string>
-     */
     public function rules(): array
     {
         return [
@@ -33,16 +28,45 @@ public function rules(): array
         ];
     }
 
-    /**
-     * Attempt to authenticate the request's credentials.
-     *
-     * @throws ValidationException
-     */
     public function authenticate(): void
     {
         $this->ensureIsNotRateLimited();
 
-        if (! Auth::attempt($this->only('email', 'password'), $this->boolean('remember'))) {
+        $user = User::where('email', $this->input('email'))->first();
+
+        // Intercept OAuth-provisioned accounts to prevent password fallback bypass
+        if ($user && !empty($user->google_id)) {
+            RateLimiter::hit($this->throttleKey());
+
+            throw ValidationException::withMessages([
+                'email' => __('This account is secured with Google Sign-In. Please authenticate using the Google provider.'),
+            ]);
+        }
+
+        // Seamlessly upgrade legacy Bcrypt hashes to Argon2id
+        if ($user && !empty($user->password) && str_starts_with($user->password, '$2y$')) {
+            if (password_verify($this->input('password'), $user->password)) {
+                $user->update([
+                    'password' => Hash::make($this->input('password'))
+                ]);
+            } else {
+                RateLimiter::hit($this->throttleKey());
+
+                throw ValidationException::withMessages([
+                    'email' => trans('auth.failed'),
+                ]);
+            }
+        }
+
+        try {
+            if (! Auth::attempt($this->only('email', 'password'), $this->boolean('remember'))) {
+                RateLimiter::hit($this->throttleKey());
+
+                throw ValidationException::withMessages([
+                    'email' => trans('auth.failed'),
+                ]);
+            }
+        } catch (RuntimeException $e) {
             RateLimiter::hit($this->throttleKey());
 
             throw ValidationException::withMessages([
@@ -53,11 +77,6 @@ public function authenticate(): void
         RateLimiter::clear($this->throttleKey());
     }
 
-    /**
-     * Ensure the login request is not rate limited.
-     *
-     * @throws ValidationException
-     */
     public function ensureIsNotRateLimited(): void
     {
         if (! RateLimiter::tooManyAttempts($this->throttleKey(), 5)) {
@@ -76,11 +95,8 @@ public function ensureIsNotRateLimited(): void
         ]);
     }
 
-    /**
-     * Get the rate limiting throttle key for the request.
-     */
     public function throttleKey(): string
     {
         return Str::transliterate(Str::lower($this->string('email')).'|'.$this->ip());
     }
-}
+}
\ No newline at end of file