diff --git a/src/pages/LoginPage.tsx b/src/pages/LoginPage.tsx
index bca66a1..9b7d28a 100644
--- a/src/pages/LoginPage.tsx
+++ b/src/pages/LoginPage.tsx
@@ -18,7 +18,7 @@ export function LoginPage() {
 
     const { error } = await login(email, password);
     if (error) {
-      setError(error.message || '登录失败');
+      setError(error);
     } else {
       navigate('/');
     }
diff --git a/src/pages/RegisterPage.tsx b/src/pages/RegisterPage.tsx
index 5b93d47..0063213 100644
--- a/src/pages/RegisterPage.tsx
+++ b/src/pages/RegisterPage.tsx
@@ -12,16 +12,33 @@ export function RegisterPage() {
   const [loading, setLoading] = useState(false);
   const [error, setError] = useState('');
 
+  // 密码强度验证
+  const passwordRequirements = [
+    { label: '至少8个字符', met: password.length >= 8 },
+    { label: '包含大写字母', met: /[A-Z]/.test(password) },
+    { label: '包含小写字母', met: /[a-z]/.test(password) },
+    { label: '包含数字', met: /\d/.test(password) },
+  ];
+
+  const meetsAllRequirements = passwordRequirements.every((req) => req.met);
+
   const handleSubmit = async (e: React.FormEvent) => {
     e.preventDefault();
     setLoading(true);
     setError('');
 
+    if (!meetsAllRequirements) {
+      setError('密码不符合要求，请检查密码格式');
+      setLoading(false);
+      return;
+    }
+
     const { error } = await register(email, password, nickname);
     if (error) {
-      setError(error.message || '注册失败');
+      setError(error);
     } else {
-      navigate('/login');
+      // 注册成功后直接跳转到首页（已登录状态）
+      navigate('/');
     }
     setLoading(false);
   };
@@ -48,16 +65,31 @@ export function RegisterPage() {
               onChange={(e) => setEmail(e.target.value)}
               required
             />
-            <TextInput
-              label="密码"
-              type="password"
-              placeholder="Create password"
-              value={password}
-              onChange={(e) => setPassword(e.target.value)}
-              required
-            />
+            <div>
+              <TextInput
+                label="密码"
+                type="password"
+                placeholder="Create password"
+                value={password}
+                onChange={(e) => setPassword(e.target.value)}
+                required
+              />
+              {/* 密码要求提示 */}
+              <Stack gap={4} mt={6}>
+                {passwordRequirements.map((req, index) => (
+                  <Text
+                    key={index}
+                    size="xs"
+                    c={req.met ? 'green' : 'dimmed'}
+                    style={{ display: 'flex', alignItems: 'center', gap: 4 }}
+                  >
+                    {req.met ? '✓' : '○'} {req.label}
+                  </Text>
+                ))}
+              </Stack>
+            </div>
             {error && <Text c="red" size="sm">{error}</Text>}
-            <Button type="submit" loading={loading} fullWidth>
+            <Button type="submit" loading={loading} fullWidth disabled={!meetsAllRequirements && password.length > 0}>
               注册
             </Button>
           </Stack>
diff --git a/src/routes.tsx b/src/routes.tsx
index 3044c74..6932975 100644
--- a/src/routes.tsx
+++ b/src/routes.tsx
@@ -1,23 +1,76 @@
-import { createBrowserRouter } from 'react-router-dom';
+import { createBrowserRouter, Navigate } from 'react-router-dom';
 import { LandingPage } from './pages/LandingPage';
 import { LoginPage } from './pages/LoginPage';
 import { RegisterPage } from './pages/RegisterPage';
 import { HomePage } from './pages/HomePage';
 import { useAppStore } from './stores';
-import { useEffect } from 'react';
+import { useState, useEffect, useRef } from 'react';
 
-// Protected Route wrapper
-function ProtectedRoute({ children }: { children: React.ReactNode }) {
+// Loading spinner component
+function AuthLoading() {
+  return (
+    <div style={{
+      display: 'flex',
+      justifyContent: 'center',
+      alignItems: 'center',
+      height: '100vh',
+      background: 'linear-gradient(135deg, #4A90D9 0%, #7AB8F5 100%)',
+    }}>
+      <div style={{
+        width: 40,
+        height: 40,
+        border: '3px solid rgba(255,255,255,0.3)',
+        borderTopColor: 'white',
+        borderRadius: '50%',
+        animation: 'spin 1s linear infinite',
+      }} />
+      <style>{`
+        @keyframes spin {
+          to { transform: rotate(360deg); }
+        }
+      `}</style>
+    </div>
+  );
+}
+
+// Auth loader - handles checkAuth and loading state
+function useAuthLoader() {
   const isAuthenticated = useAppStore((state) => state.isAuthenticated);
   const checkAuth = useAppStore((state) => state.checkAuth);
   const isLoading = useAppStore((state) => state.isLoading);
 
+  // 使用 ref 跟踪是否已检查过，避免重复检查
+  const checkedRef = useRef(false);
+
   useEffect(() => {
-    checkAuth();
-  }, [checkAuth]);
+    // 标记已检查，但只在未登录时调用 checkAuth
+    if (!checkedRef.current) {
+      checkedRef.current = true;
+      // 如果未登录，才需要检查
+      if (!isAuthenticated) {
+        checkAuth();
+      }
+    }
+  }, [checkAuth, isAuthenticated]);
+
+  // 如果已登录，直接返回，不再显示 Loading
+  if (isAuthenticated) {
+    return { isAuthenticated: true, isLoading: false };
+  }
+
+  return { isAuthenticated: false, isLoading };
+}
+
+// Protected Route wrapper
+function ProtectedRoute({ children }: { children: React.ReactNode }) {
+  const { isAuthenticated, isLoading } = useAuthLoader();
 
   if (isLoading) {
-    return null; // Or a loading spinner
+    return <AuthLoading />;
+  }
+
+  if (!isAuthenticated) {
+    return <Navigate to="/login" replace />;
   }
 
   return <>{children}</>;
@@ -25,15 +78,14 @@ function ProtectedRoute({ children }: { children: React.ReactNode }) {
 
 // Public Route wrapper (redirects to home if authenticated)
 function PublicRoute({ children }: { children: React.ReactNode }) {
-  const isAuthenticated = useAppStore((state) => state.isAuthenticated);
-  const checkAuth = useAppStore((state) => state.checkAuth);
+  const { isAuthenticated, isLoading } = useAuthLoader();
 
-  useEffect(() => {
-    checkAuth();
-  }, [checkAuth]);
+  if (isLoading) {
+    return <AuthLoading />;
+  }
 
   if (isAuthenticated) {
-    return <HomePage />;
+    return <Navigate to="/home" replace />;
   }
 
   return <>{children}</>;
@@ -42,6 +94,10 @@ function PublicRoute({ children }: { children: React.ReactNode }) {
 export const router = createBrowserRouter([
   {
     path: '/',
+    element: <Navigate to="/home" replace />,
+  },
+  {
+    path: '/landing',
     element: (
       <PublicRoute>
         <LandingPage />
diff --git a/src/stores/index.ts b/src/stores/index.ts
index aa54c49..ffa1865 100644
--- a/src/stores/index.ts
+++ b/src/stores/index.ts
@@ -93,7 +93,7 @@ export const useAppStore = create<AppState>()(
 
       saveNotes: async (content) => {
         try {
-          const notes = await api.notes.save(content);
+          const notes = await api.notes.update(content);
           set({ notes });
         } catch (error) {
           console.error('Failed to save notes:', error);
@@ -143,7 +143,9 @@ export const useAppStore = create<AppState>()(
           set({ user, isAuthenticated: true });
           return { error: null };
         } catch (error: any) {
-          return { error: error.message || '登录失败' };
+          // 确保返回字符串错误信息
+          const errorMessage = error.message || '登录失败，请检查邮箱和密码';
+          return { error: errorMessage };
         }
       },
 
@@ -154,7 +156,9 @@ export const useAppStore = create<AppState>()(
           set({ user, isAuthenticated: true });
           return { error: null };
         } catch (error: any) {
-          return { error: error.message || '注册失败' };
+          // 确保返回字符串错误信息
+          const errorMessage = error.message || '注册失败，请稍后重试';
+          return { error: errorMessage };
         }
       },