feat: 新增登录页 + 主题改橙红对齐设计稿

- 新增登录页（Google / 手机号 / 邮箱 + 游客浏览 + 首登送金币）
- seedColor 改橙红 #FF5B3D，themeMode 改 dark，背景对齐设计稿 #0B0C10
- app 启动入口改为 LoginPage

lib/app.dart

@@ -11,7 +11,7 @@ import 'core/data/services/engagement_controller.dart';
 import 'core/data/services/playback_session.dart';
 import 'core/data/services/video_player_port.dart';
 import 'l10n/app_localizations.dart';
-import 'pages/home/home_view.dart';
+import 'pages/login/login_view.dart';
 
 class LumaDramaApp extends StatelessWidget {
   const LumaDramaApp({super.key, this.playerFactory = VideoPlayerPort.new});
@@ -49,23 +49,23 @@ class LumaDramaApp extends StatelessWidget {
             return supported.first;
           },
           debugShowCheckedModeBanner: false,
-          themeMode: ThemeMode.system,
+          themeMode: ThemeMode.dark,
           theme: ThemeData(
             useMaterial3: true,
             colorScheme: ColorScheme.fromSeed(
-              seedColor: const Color(0xFF6D4AFF),
+              seedColor: const Color(0xFFFF5B3D),
             ),
-            scaffoldBackgroundColor: const Color(0xFFF8F7FC),
+            scaffoldBackgroundColor: const Color(0xFF0B0C10),
           ),
           darkTheme: ThemeData(
             useMaterial3: true,
             colorScheme: ColorScheme.fromSeed(
-              seedColor: const Color(0xFF9B86FF),
+              seedColor: const Color(0xFFFF5B3D),
               brightness: Brightness.dark,
             ),
-            scaffoldBackgroundColor: const Color(0xFF101019),
+            scaffoldBackgroundColor: const Color(0xFF0B0C10),
           ),
-          home: const HomePage(),
+          home: const LoginPage(),
         ),
       ),
     );

lib/pages/login/login_view.dart

@@ -0,0 +1,341 @@
+// Author: fruit.com.cn
+
+import 'package:flutter/material.dart';
+
+import '../home/home_view.dart';
+
+/// 登录页：Google / 手机号 / 邮箱 三种登录入口 + 游客浏览。
+/// 当前为 UI 占位实现，真实登录逻辑在接入后端 /app/auth/** 后补充。
+class LoginPage extends StatefulWidget {
+  const LoginPage({super.key});
+
+  @override
+  State<LoginPage> createState() => _LoginPageState();
+}
+
+class _LoginPageState extends State<LoginPage> {
+  static const _orange = Color(0xFFFF5B3D);
+  static const _purple = Color(0xFF9278EA);
+
+  void _enterHome() {
+    Navigator.of(context).pushReplacement(
+      MaterialPageRoute<void>(builder: (_) => const HomePage()),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: SafeArea(
+        child: Column(
+          children: [
+            // 顶部：关闭 + 游客浏览
+            Padding(
+              padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 8),
+              child: Row(
+                mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                children: [
+                  _IconButton(icon: Icons.close, onTap: () {}),
+                  TextButton(
+                    onPressed: _enterHome,
+                    style: TextButton.styleFrom(
+                      foregroundColor: Colors.white54,
+                      backgroundColor: Colors.white.withValues(alpha: 0.05),
+                      padding: const EdgeInsets.symmetric(
+                        horizontal: 14,
+                        vertical: 8,
+                      ),
+                      shape: const StadiumBorder(),
+                    ),
+                    child: const Text('Guest Explore'),
+                  ),
+                ],
+              ),
+            ),
+            // 中央内容
+            Expanded(
+              child: Center(
+                child: Padding(
+                  padding: const EdgeInsets.symmetric(horizontal: 28),
+                  child: Column(
+                    mainAxisSize: MainAxisSize.min,
+                    children: [
+                      const _BrandLogo(),
+                      const SizedBox(height: 20),
+                      const Text(
+                        'DramaPulse',
+                        style: TextStyle(
+                          fontSize: 30,
+                          fontWeight: FontWeight.w800,
+                          color: Colors.white,
+                        ),
+                      ),
+                      const SizedBox(height: 8),
+                      const Text(
+                        'Sign in to sync your progress and coins',
+                        textAlign: TextAlign.center,
+                        style: TextStyle(
+                          fontSize: 14,
+                          color: Colors.white54,
+                        ),
+                      ),
+                      const SizedBox(height: 36),
+                      _GoogleButton(onTap: _enterHome),
+                      const SizedBox(height: 14),
+                      _DarkButton(
+                        icon: Icons.phone_iphone,
+                        iconColor: _orange,
+                        label: 'Continue with Phone Number',
+                        onTap: _enterHome,
+                      ),
+                      const SizedBox(height: 14),
+                      _DarkButton(
+                        icon: Icons.email_outlined,
+                        iconColor: _purple,
+                        label: 'Continue with Email',
+                        onTap: _enterHome,
+                      ),
+                      const SizedBox(height: 32),
+                      const _BonusPill(),
+                    ],
+                  ),
+                ),
+              ),
+            ),
+            // 底部协议
+            const Padding(
+              padding: EdgeInsets.only(bottom: 24),
+              child: Text(
+                'By continuing, you agree to DramaPulse\'s\n'
+                'Terms of Service · Privacy Policy · Content Policy',
+                textAlign: TextAlign.center,
+                style: TextStyle(fontSize: 11, color: Colors.white38),
+              ),
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}
+
+class _IconButton extends StatelessWidget {
+  const _IconButton({required this.icon, required this.onTap});
+
+  final IconData icon;
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    return InkWell(
+      onTap: onTap,
+      borderRadius: BorderRadius.circular(24),
+      child: Container(
+        width: 40,
+        height: 40,
+        decoration: BoxDecoration(
+          color: Colors.white.withValues(alpha: 0.05),
+          border: Border.all(color: Colors.white12),
+          shape: BoxShape.circle,
+        ),
+        child: Icon(icon, color: Colors.white54, size: 20),
+      ),
+    );
+  }
+}
+
+class _BrandLogo extends StatelessWidget {
+  const _BrandLogo();
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      width: 80,
+      height: 80,
+      decoration: BoxDecoration(
+        gradient: const LinearGradient(
+          begin: Alignment.topLeft,
+          end: Alignment.bottomRight,
+          colors: [Color(0xFFFF5B3D), Color(0xFFD8536C), Color(0xFF9278EA)],
+        ),
+        borderRadius: BorderRadius.circular(20),
+        border: Border.all(color: Colors.white24),
+      ),
+      child: const Icon(Icons.play_arrow_rounded, color: Colors.white, size: 40),
+    );
+  }
+}
+
+class _GoogleButton extends StatelessWidget {
+  const _GoogleButton({required this.onTap});
+
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    return _AuthButton(
+      onTap: onTap,
+      background: Colors.white,
+      child: Row(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: [
+          const _GoogleG(),
+          const SizedBox(width: 12),
+          Text(
+            'Continue with Google',
+            style: TextStyle(
+              fontSize: 14,
+              fontWeight: FontWeight.w600,
+              color: Colors.grey.shade900,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+/// 简化版 Google「G」logo。
+class _GoogleG extends StatelessWidget {
+  const _GoogleG();
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      width: 20,
+      height: 20,
+      decoration: const BoxDecoration(
+        shape: BoxShape.circle,
+        color: Color(0xFF4285F4),
+      ),
+      child: const Center(
+        child: Text(
+          'G',
+          style: TextStyle(
+            color: Colors.white,
+            fontSize: 13,
+            fontWeight: FontWeight.w700,
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+class _DarkButton extends StatelessWidget {
+  const _DarkButton({
+    required this.icon,
+    required this.iconColor,
+    required this.label,
+    required this.onTap,
+  });
+
+  final IconData icon;
+  final Color iconColor;
+  final String label;
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    return _AuthButton(
+      onTap: onTap,
+      background: const Color(0xFF161822),
+      border: const Color(0xFF232634),
+      child: Row(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: [
+          Icon(icon, color: iconColor, size: 20),
+          const SizedBox(width: 12),
+          Text(
+            label,
+            style: const TextStyle(
+              fontSize: 14,
+              fontWeight: FontWeight.w500,
+              color: Colors.white,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+class _AuthButton extends StatelessWidget {
+  const _AuthButton({
+    required this.onTap,
+    required this.background,
+    required this.child,
+    this.border,
+  });
+
+  final VoidCallback onTap;
+  final Color background;
+  final Color? border;
+  final Widget child;
+
+  @override
+  Widget build(BuildContext context) {
+    return SizedBox(
+      width: double.infinity,
+      height: 52,
+      child: Material(
+        color: background,
+        shape: RoundedRectangleBorder(
+          borderRadius: BorderRadius.circular(16),
+          side: border == null ? BorderSide.none : BorderSide(color: border!),
+        ),
+        child: InkWell(
+          onTap: onTap,
+          borderRadius: BorderRadius.circular(16),
+          child: child,
+        ),
+      ),
+    );
+  }
+}
+
+class _BonusPill extends StatelessWidget {
+  const _BonusPill();
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 8),
+      decoration: BoxDecoration(
+        color: Colors.white.withValues(alpha: 0.04),
+        border: Border.all(color: Colors.white12),
+        borderRadius: BorderRadius.circular(999),
+      ),
+      child: Row(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          Container(
+            width: 6,
+            height: 6,
+            decoration: const BoxDecoration(
+              color: Color(0xFF34D399),
+              shape: BoxShape.circle,
+            ),
+          ),
+          const SizedBox(width: 8),
+          const Text(
+            'Get ',
+            style: TextStyle(fontSize: 11, color: Colors.white54),
+          ),
+          const Text(
+            '100 Free Bonus Coins',
+            style: TextStyle(
+              fontSize: 11,
+              fontWeight: FontWeight.w600,
+              color: Colors.white,
+            ),
+          ),
+          const Text(
+            ' upon first sign-in',
+            style: TextStyle(fontSize: 11, color: Colors.white54),
+          ),
+        ],
+      ),
+    );
+  }
+}