diff --git a/.gitignore b/.gitignore
index f8c6c2e..2a6edee 100644
--- a/.gitignore
+++ b/.gitignore
@@ -41,3 +41,4 @@ app-example
 # generated native folders
 /ios
 /android
+.git-credentials
diff --git a/app/(auth)/_layout.tsx b/app/(auth)/_layout.tsx
new file mode 100644
index 0000000..9ac3ffe
--- /dev/null
+++ b/app/(auth)/_layout.tsx
@@ -0,0 +1,15 @@
+import { Stack } from 'expo-router';
+import { AppColors } from '@/constants/theme';
+
+export default function AuthLayout() {
+  return (
+    <Stack
+      screenOptions={{
+        headerShown: false,
+        contentStyle: { backgroundColor: AppColors.background },
+      }}
+    >
+      <Stack.Screen name="login" />
+    </Stack>
+  );
+}
diff --git a/app/(auth)/login.tsx b/app/(auth)/login.tsx
new file mode 100644
index 0000000..ed77ae5
--- /dev/null
+++ b/app/(auth)/login.tsx
@@ -0,0 +1,210 @@
+import React, { useState, useCallback } from 'react';
+import {
+  View,
+  Text,
+  StyleSheet,
+  KeyboardAvoidingView,
+  Platform,
+  ScrollView,
+  TouchableOpacity,
+  Image,
+} from 'react-native';
+import { router } from 'expo-router';
+import { useAuth } from '@/contexts/AuthContext';
+import { Button } from '@/components/ui/Button';
+import { Input } from '@/components/ui/Input';
+import { ErrorMessage } from '@/components/ui/ErrorMessage';
+import { AppColors, BorderRadius, FontSizes, Spacing } from '@/constants/theme';
+
+export default function LoginScreen() {
+  const { login, isLoading, error, clearError } = useAuth();
+  const [username, setUsername] = useState('');
+  const [password, setPassword] = useState('');
+  const [validationError, setValidationError] = useState<string | null>(null);
+
+  const handleLogin = useCallback(async () => {
+    // Clear previous errors
+    clearError();
+    setValidationError(null);
+
+    // Validate
+    if (!username.trim()) {
+      setValidationError('Username is required');
+      return;
+    }
+    if (!password.trim()) {
+      setValidationError('Password is required');
+      return;
+    }
+
+    const success = await login({ username: username.trim(), password });
+
+    if (success) {
+      router.replace('/(tabs)');
+    }
+  }, [username, password, login, clearError]);
+
+  const displayError = validationError || error?.message;
+
+  return (
+    <KeyboardAvoidingView
+      style={styles.container}
+      behavior={Platform.OS === 'ios' ? 'padding' : 'height'}
+    >
+      <ScrollView
+        contentContainerStyle={styles.scrollContent}
+        keyboardShouldPersistTaps="handled"
+        showsVerticalScrollIndicator={false}
+      >
+        {/* Logo / Header */}
+        <View style={styles.header}>
+          <View style={styles.logoContainer}>
+            <Text style={styles.logoText}>WellNuo</Text>
+          </View>
+          <Text style={styles.title}>Welcome Back</Text>
+          <Text style={styles.subtitle}>Sign in to continue monitoring your loved ones</Text>
+        </View>
+
+        {/* Form */}
+        <View style={styles.form}>
+          {displayError && (
+            <ErrorMessage
+              message={displayError}
+              onDismiss={() => {
+                clearError();
+                setValidationError(null);
+              }}
+            />
+          )}
+
+          <Input
+            label="Username"
+            placeholder="Enter your username"
+            leftIcon="person-outline"
+            value={username}
+            onChangeText={(text) => {
+              setUsername(text);
+              setValidationError(null);
+            }}
+            autoCapitalize="none"
+            autoCorrect={false}
+            editable={!isLoading}
+          />
+
+          <Input
+            label="Password"
+            placeholder="Enter your password"
+            leftIcon="lock-closed-outline"
+            secureTextEntry
+            value={password}
+            onChangeText={(text) => {
+              setPassword(text);
+              setValidationError(null);
+            }}
+            editable={!isLoading}
+            onSubmitEditing={handleLogin}
+            returnKeyType="done"
+          />
+
+          <TouchableOpacity style={styles.forgotPassword}>
+            <Text style={styles.forgotPasswordText}>Forgot Password?</Text>
+          </TouchableOpacity>
+
+          <Button
+            title="Sign In"
+            onPress={handleLogin}
+            loading={isLoading}
+            fullWidth
+            size="lg"
+          />
+        </View>
+
+        {/* Footer */}
+        <View style={styles.footer}>
+          <Text style={styles.footerText}>Don't have an account? </Text>
+          <TouchableOpacity>
+            <Text style={styles.footerLink}>Create Account</Text>
+          </TouchableOpacity>
+        </View>
+
+        {/* Version Info */}
+        <Text style={styles.version}>WellNuo v1.0.0</Text>
+      </ScrollView>
+    </KeyboardAvoidingView>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    backgroundColor: AppColors.background,
+  },
+  scrollContent: {
+    flexGrow: 1,
+    paddingHorizontal: Spacing.lg,
+    paddingTop: Spacing.xxl + Spacing.xl,
+    paddingBottom: Spacing.xl,
+  },
+  header: {
+    alignItems: 'center',
+    marginBottom: Spacing.xl,
+  },
+  logoContainer: {
+    width: 80,
+    height: 80,
+    borderRadius: BorderRadius.xl,
+    backgroundColor: AppColors.primary,
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginBottom: Spacing.lg,
+  },
+  logoText: {
+    fontSize: FontSizes.lg,
+    fontWeight: '700',
+    color: AppColors.white,
+  },
+  title: {
+    fontSize: FontSizes['2xl'],
+    fontWeight: '700',
+    color: AppColors.textPrimary,
+    marginBottom: Spacing.xs,
+  },
+  subtitle: {
+    fontSize: FontSizes.base,
+    color: AppColors.textSecondary,
+    textAlign: 'center',
+  },
+  form: {
+    marginBottom: Spacing.xl,
+  },
+  forgotPassword: {
+    alignSelf: 'flex-end',
+    marginBottom: Spacing.lg,
+    marginTop: -Spacing.sm,
+  },
+  forgotPasswordText: {
+    fontSize: FontSizes.sm,
+    color: AppColors.primary,
+    fontWeight: '500',
+  },
+  footer: {
+    flexDirection: 'row',
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginBottom: Spacing.xl,
+  },
+  footerText: {
+    fontSize: FontSizes.base,
+    color: AppColors.textSecondary,
+  },
+  footerLink: {
+    fontSize: FontSizes.base,
+    color: AppColors.primary,
+    fontWeight: '600',
+  },
+  version: {
+    textAlign: 'center',
+    fontSize: FontSizes.xs,
+    color: AppColors.textMuted,
+  },
+});
diff --git a/app/(tabs)/_layout.tsx b/app/(tabs)/_layout.tsx
index 54e11d0..4d39bec 100644
--- a/app/(tabs)/_layout.tsx
+++ b/app/(tabs)/_layout.tsx
@@ -1,33 +1,60 @@
 import { Tabs } from 'expo-router';
 import React from 'react';
+import { Ionicons } from '@expo/vector-icons';
 
 import { HapticTab } from '@/components/haptic-tab';
-import { IconSymbol } from '@/components/ui/icon-symbol';
-import { Colors } from '@/constants/theme';
+import { AppColors } from '@/constants/theme';
 import { useColorScheme } from '@/hooks/use-color-scheme';
 
 export default function TabLayout() {
   const colorScheme = useColorScheme();
+  const isDark = colorScheme === 'dark';
 
   return (
     <Tabs
       screenOptions={{
-        tabBarActiveTintColor: Colors[colorScheme ?? 'light'].tint,
+        tabBarActiveTintColor: AppColors.primary,
+        tabBarInactiveTintColor: isDark ? '#9BA1A6' : '#687076',
+        tabBarStyle: {
+          backgroundColor: isDark ? '#151718' : AppColors.background,
+          borderTopColor: isDark ? '#2D3135' : AppColors.border,
+        },
         headerShown: false,
         tabBarButton: HapticTab,
-      }}>
+      }}
+    >
       <Tabs.Screen
         name="index"
         options={{
-          title: 'Home',
-          tabBarIcon: ({ color }) => <IconSymbol size={28} name="house.fill" color={color} />,
+          title: 'Patients',
+          tabBarIcon: ({ color, size }) => (
+            <Ionicons name="people" size={size} color={color} />
+          ),
         }}
       />
+      <Tabs.Screen
+        name="chat"
+        options={{
+          title: 'Chat',
+          tabBarIcon: ({ color, size }) => (
+            <Ionicons name="chatbubble-ellipses" size={size} color={color} />
+          ),
+        }}
+      />
+      <Tabs.Screen
+        name="profile"
+        options={{
+          title: 'Profile',
+          tabBarIcon: ({ color, size }) => (
+            <Ionicons name="person" size={size} color={color} />
+          ),
+        }}
+      />
+      {/* Hide explore tab */}
       <Tabs.Screen
         name="explore"
         options={{
-          title: 'Explore',
-          tabBarIcon: ({ color }) => <IconSymbol size={28} name="paperplane.fill" color={color} />,
+          href: null,
         }}
       />
     </Tabs>
diff --git a/app/(tabs)/chat.tsx b/app/(tabs)/chat.tsx
new file mode 100644
index 0000000..a27ceb4
--- /dev/null
+++ b/app/(tabs)/chat.tsx
@@ -0,0 +1,321 @@
+import React, { useState, useCallback, useRef } from 'react';
+import {
+  View,
+  Text,
+  StyleSheet,
+  FlatList,
+  TextInput,
+  TouchableOpacity,
+  KeyboardAvoidingView,
+  Platform,
+} from 'react-native';
+import { Ionicons } from '@expo/vector-icons';
+import { SafeAreaView } from 'react-native-safe-area-context';
+import { api } from '@/services/api';
+import { AppColors, BorderRadius, FontSizes, Spacing } from '@/constants/theme';
+import type { Message } from '@/types';
+
+export default function ChatScreen() {
+  const [messages, setMessages] = useState<Message[]>([
+    {
+      id: '1',
+      role: 'assistant',
+      content: 'Hello! I\'m Julia, your AI assistant. How can I help you today?',
+      timestamp: new Date(),
+    },
+  ]);
+  const [input, setInput] = useState('');
+  const [isSending, setIsSending] = useState(false);
+  const flatListRef = useRef<FlatList>(null);
+
+  const handleSend = useCallback(async () => {
+    const trimmedInput = input.trim();
+    if (!trimmedInput || isSending) return;
+
+    const userMessage: Message = {
+      id: Date.now().toString(),
+      role: 'user',
+      content: trimmedInput,
+      timestamp: new Date(),
+    };
+
+    setMessages((prev) => [...prev, userMessage]);
+    setInput('');
+    setIsSending(true);
+
+    try {
+      const response = await api.sendMessage(trimmedInput);
+
+      if (response.ok && response.data?.response) {
+        const assistantMessage: Message = {
+          id: (Date.now() + 1).toString(),
+          role: 'assistant',
+          content: response.data.response.body,
+          timestamp: new Date(),
+        };
+        setMessages((prev) => [...prev, assistantMessage]);
+      } else {
+        const errorMessage: Message = {
+          id: (Date.now() + 1).toString(),
+          role: 'assistant',
+          content: 'Sorry, I encountered an error. Please try again.',
+          timestamp: new Date(),
+        };
+        setMessages((prev) => [...prev, errorMessage]);
+      }
+    } catch (error) {
+      const errorMessage: Message = {
+        id: (Date.now() + 1).toString(),
+        role: 'assistant',
+        content: 'Sorry, I couldn\'t connect to the server. Please check your internet connection.',
+        timestamp: new Date(),
+      };
+      setMessages((prev) => [...prev, errorMessage]);
+    } finally {
+      setIsSending(false);
+    }
+  }, [input, isSending]);
+
+  const renderMessage = ({ item }: { item: Message }) => {
+    const isUser = item.role === 'user';
+
+    return (
+      <View
+        style={[
+          styles.messageContainer,
+          isUser ? styles.userMessageContainer : styles.assistantMessageContainer,
+        ]}
+      >
+        {!isUser && (
+          <View style={styles.avatarContainer}>
+            <Text style={styles.avatarText}>J</Text>
+          </View>
+        )}
+        <View
+          style={[
+            styles.messageBubble,
+            isUser ? styles.userBubble : styles.assistantBubble,
+          ]}
+        >
+          <Text
+            style={[
+              styles.messageText,
+              isUser ? styles.userMessageText : styles.assistantMessageText,
+            ]}
+          >
+            {item.content}
+          </Text>
+          <Text style={[styles.timestamp, isUser && styles.userTimestamp]}>
+            {item.timestamp.toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })}
+          </Text>
+        </View>
+      </View>
+    );
+  };
+
+  return (
+    <SafeAreaView style={styles.container} edges={['top']}>
+      {/* Header */}
+      <View style={styles.header}>
+        <View style={styles.headerInfo}>
+          <View style={styles.headerAvatar}>
+            <Text style={styles.headerAvatarText}>J</Text>
+          </View>
+          <View>
+            <Text style={styles.headerTitle}>Julia AI</Text>
+            <Text style={styles.headerSubtitle}>
+              {isSending ? 'Typing...' : 'Online'}
+            </Text>
+          </View>
+        </View>
+        <TouchableOpacity style={styles.headerButton}>
+          <Ionicons name="ellipsis-vertical" size={24} color={AppColors.textPrimary} />
+        </TouchableOpacity>
+      </View>
+
+      {/* Messages */}
+      <KeyboardAvoidingView
+        style={styles.chatContainer}
+        behavior={Platform.OS === 'ios' ? 'padding' : undefined}
+        keyboardVerticalOffset={Platform.OS === 'ios' ? 90 : 0}
+      >
+        <FlatList
+          ref={flatListRef}
+          data={messages}
+          keyExtractor={(item) => item.id}
+          renderItem={renderMessage}
+          contentContainerStyle={styles.messagesList}
+          showsVerticalScrollIndicator={false}
+          onContentSizeChange={() => flatListRef.current?.scrollToEnd({ animated: true })}
+        />
+
+        {/* Input */}
+        <View style={styles.inputContainer}>
+          <TextInput
+            style={styles.input}
+            placeholder="Type a message..."
+            placeholderTextColor={AppColors.textMuted}
+            value={input}
+            onChangeText={setInput}
+            multiline
+            maxLength={1000}
+            editable={!isSending}
+            onSubmitEditing={handleSend}
+          />
+          <TouchableOpacity
+            style={[styles.sendButton, (!input.trim() || isSending) && styles.sendButtonDisabled]}
+            onPress={handleSend}
+            disabled={!input.trim() || isSending}
+          >
+            <Ionicons
+              name={isSending ? 'hourglass' : 'send'}
+              size={20}
+              color={input.trim() && !isSending ? AppColors.white : AppColors.textMuted}
+            />
+          </TouchableOpacity>
+        </View>
+      </KeyboardAvoidingView>
+    </SafeAreaView>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    backgroundColor: AppColors.surface,
+  },
+  header: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    justifyContent: 'space-between',
+    paddingHorizontal: Spacing.md,
+    paddingVertical: Spacing.sm,
+    backgroundColor: AppColors.background,
+    borderBottomWidth: 1,
+    borderBottomColor: AppColors.border,
+  },
+  headerInfo: {
+    flexDirection: 'row',
+    alignItems: 'center',
+  },
+  headerAvatar: {
+    width: 40,
+    height: 40,
+    borderRadius: BorderRadius.full,
+    backgroundColor: AppColors.success,
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginRight: Spacing.sm,
+  },
+  headerAvatarText: {
+    fontSize: FontSizes.lg,
+    fontWeight: '600',
+    color: AppColors.white,
+  },
+  headerTitle: {
+    fontSize: FontSizes.lg,
+    fontWeight: '600',
+    color: AppColors.textPrimary,
+  },
+  headerSubtitle: {
+    fontSize: FontSizes.sm,
+    color: AppColors.success,
+  },
+  headerButton: {
+    padding: Spacing.xs,
+  },
+  chatContainer: {
+    flex: 1,
+  },
+  messagesList: {
+    padding: Spacing.md,
+    paddingBottom: Spacing.lg,
+  },
+  messageContainer: {
+    flexDirection: 'row',
+    marginBottom: Spacing.md,
+    alignItems: 'flex-end',
+  },
+  userMessageContainer: {
+    justifyContent: 'flex-end',
+  },
+  assistantMessageContainer: {
+    justifyContent: 'flex-start',
+  },
+  avatarContainer: {
+    width: 32,
+    height: 32,
+    borderRadius: BorderRadius.full,
+    backgroundColor: AppColors.success,
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginRight: Spacing.xs,
+  },
+  avatarText: {
+    fontSize: FontSizes.sm,
+    fontWeight: '600',
+    color: AppColors.white,
+  },
+  messageBubble: {
+    maxWidth: '75%',
+    padding: Spacing.sm + 4,
+    borderRadius: BorderRadius.lg,
+  },
+  userBubble: {
+    backgroundColor: AppColors.primary,
+    borderBottomRightRadius: BorderRadius.sm,
+  },
+  assistantBubble: {
+    backgroundColor: AppColors.background,
+    borderBottomLeftRadius: BorderRadius.sm,
+  },
+  messageText: {
+    fontSize: FontSizes.base,
+    lineHeight: 22,
+  },
+  userMessageText: {
+    color: AppColors.white,
+  },
+  assistantMessageText: {
+    color: AppColors.textPrimary,
+  },
+  timestamp: {
+    fontSize: FontSizes.xs,
+    color: AppColors.textMuted,
+    marginTop: Spacing.xs,
+    alignSelf: 'flex-end',
+  },
+  userTimestamp: {
+    color: 'rgba(255,255,255,0.7)',
+  },
+  inputContainer: {
+    flexDirection: 'row',
+    alignItems: 'flex-end',
+    padding: Spacing.md,
+    backgroundColor: AppColors.background,
+    borderTopWidth: 1,
+    borderTopColor: AppColors.border,
+  },
+  input: {
+    flex: 1,
+    backgroundColor: AppColors.surface,
+    borderRadius: BorderRadius.xl,
+    paddingHorizontal: Spacing.md,
+    paddingVertical: Spacing.sm,
+    fontSize: FontSizes.base,
+    color: AppColors.textPrimary,
+    maxHeight: 100,
+    marginRight: Spacing.sm,
+  },
+  sendButton: {
+    width: 44,
+    height: 44,
+    borderRadius: BorderRadius.full,
+    backgroundColor: AppColors.primary,
+    justifyContent: 'center',
+    alignItems: 'center',
+  },
+  sendButtonDisabled: {
+    backgroundColor: AppColors.surface,
+  },
+});
diff --git a/app/(tabs)/index.tsx b/app/(tabs)/index.tsx
index 786b736..5f1a03d 100644
--- a/app/(tabs)/index.tsx
+++ b/app/(tabs)/index.tsx
@@ -1,98 +1,311 @@
-import { Image } from 'expo-image';
-import { Platform, StyleSheet } from 'react-native';
+import React, { useState, useEffect, useCallback } from 'react';
+import {
+  View,
+  Text,
+  StyleSheet,
+  FlatList,
+  TouchableOpacity,
+  RefreshControl,
+} from 'react-native';
+import { router } from 'expo-router';
+import { Ionicons } from '@expo/vector-icons';
+import { SafeAreaView } from 'react-native-safe-area-context';
+import { api } from '@/services/api';
+import { useAuth } from '@/contexts/AuthContext';
+import { LoadingSpinner } from '@/components/ui/LoadingSpinner';
+import { FullScreenError } from '@/components/ui/ErrorMessage';
+import { AppColors, BorderRadius, FontSizes, Spacing } from '@/constants/theme';
+import type { Patient } from '@/types';
 
-import { HelloWave } from '@/components/hello-wave';
-import ParallaxScrollView from '@/components/parallax-scroll-view';
-import { ThemedText } from '@/components/themed-text';
-import { ThemedView } from '@/components/themed-view';
-import { Link } from 'expo-router';
+export default function PatientsListScreen() {
+  const { user } = useAuth();
+  const [patients, setPatients] = useState<Patient[]>([]);
+  const [isLoading, setIsLoading] = useState(true);
+  const [isRefreshing, setIsRefreshing] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const loadPatients = useCallback(async (showLoading = true) => {
+    if (showLoading) setIsLoading(true);
+    setError(null);
+
+    try {
+      const response = await api.getPatients();
+
+      if (response.ok && response.data) {
+        setPatients(response.data.patients);
+      } else {
+        setError(response.error?.message || 'Failed to load patients');
+      }
+    } catch (err) {
+      setError(err instanceof Error ? err.message : 'An error occurred');
+    } finally {
+      setIsLoading(false);
+      setIsRefreshing(false);
+    }
+  }, []);
+
+  useEffect(() => {
+    loadPatients();
+  }, [loadPatients]);
+
+  const handleRefresh = useCallback(() => {
+    setIsRefreshing(true);
+    loadPatients(false);
+  }, [loadPatients]);
+
+  const handlePatientPress = (patient: Patient) => {
+    router.push(`/patients/${patient.id}`);
+  };
+
+  const renderPatientCard = ({ item }: { item: Patient }) => (
+    <TouchableOpacity
+      style={styles.patientCard}
+      onPress={() => handlePatientPress(item)}
+      activeOpacity={0.7}
+    >
+      <View style={styles.patientInfo}>
+        <View style={styles.avatarContainer}>
+          <Text style={styles.avatarText}>
+            {item.name.charAt(0).toUpperCase()}
+          </Text>
+          <View
+            style={[
+              styles.statusIndicator,
+              item.status === 'online' ? styles.online : styles.offline,
+            ]}
+          />
+        </View>
+
+        <View style={styles.patientDetails}>
+          <Text style={styles.patientName}>{item.name}</Text>
+          <Text style={styles.patientRelationship}>{item.relationship}</Text>
+          <Text style={styles.lastActivity}>
+            <Ionicons name="time-outline" size={12} color={AppColors.textMuted} />{' '}
+            {item.last_activity}
+          </Text>
+        </View>
+      </View>
+
+      {item.health_data && (
+        <View style={styles.healthStats}>
+          <View style={styles.statItem}>
+            <Ionicons name="heart-outline" size={16} color={AppColors.error} />
+            <Text style={styles.statValue}>{item.health_data.heart_rate}</Text>
+            <Text style={styles.statLabel}>BPM</Text>
+          </View>
+          <View style={styles.statItem}>
+            <Ionicons name="footsteps-outline" size={16} color={AppColors.primary} />
+            <Text style={styles.statValue}>{item.health_data.steps?.toLocaleString()}</Text>
+            <Text style={styles.statLabel}>Steps</Text>
+          </View>
+          <View style={styles.statItem}>
+            <Ionicons name="moon-outline" size={16} color={AppColors.primaryDark} />
+            <Text style={styles.statValue}>{item.health_data.sleep_hours}h</Text>
+            <Text style={styles.statLabel}>Sleep</Text>
+          </View>
+        </View>
+      )}
+
+      <Ionicons
+        name="chevron-forward"
+        size={20}
+        color={AppColors.textMuted}
+        style={styles.chevron}
+      />
+    </TouchableOpacity>
+  );
+
+  if (isLoading) {
+    return <LoadingSpinner fullScreen message="Loading patients..." />;
+  }
+
+  if (error) {
+    return <FullScreenError message={error} onRetry={() => loadPatients()} />;
+  }
 
-export default function HomeScreen() {
   return (
-    <ParallaxScrollView
-      headerBackgroundColor={{ light: '#A1CEDC', dark: '#1D3D47' }}
-      headerImage={
-        <Image
-          source={require('@/assets/images/partial-react-logo.png')}
-          style={styles.reactLogo}
-        />
-      }>
-      <ThemedView style={styles.titleContainer}>
-        <ThemedText type="title">Welcome!</ThemedText>
-        <HelloWave />
-      </ThemedView>
-      <ThemedView style={styles.stepContainer}>
-        <ThemedText type="subtitle">Step 1: Try it</ThemedText>
-        <ThemedText>
-          Edit <ThemedText type="defaultSemiBold">app/(tabs)/index.tsx</ThemedText> to see changes.
-          Press{' '}
-          <ThemedText type="defaultSemiBold">
-            {Platform.select({
-              ios: 'cmd + d',
-              android: 'cmd + m',
-              web: 'F12',
-            })}
-          </ThemedText>{' '}
-          to open developer tools.
-        </ThemedText>
-      </ThemedView>
-      <ThemedView style={styles.stepContainer}>
-        <Link href="/modal">
-          <Link.Trigger>
-            <ThemedText type="subtitle">Step 2: Explore</ThemedText>
-          </Link.Trigger>
-          <Link.Preview />
-          <Link.Menu>
-            <Link.MenuAction title="Action" icon="cube" onPress={() => alert('Action pressed')} />
-            <Link.MenuAction
-              title="Share"
-              icon="square.and.arrow.up"
-              onPress={() => alert('Share pressed')}
-            />
-            <Link.Menu title="More" icon="ellipsis">
-              <Link.MenuAction
-                title="Delete"
-                icon="trash"
-                destructive
-                onPress={() => alert('Delete pressed')}
-              />
-            </Link.Menu>
-          </Link.Menu>
-        </Link>
+    <SafeAreaView style={styles.container} edges={['top']}>
+      {/* Header */}
+      <View style={styles.header}>
+        <View>
+          <Text style={styles.greeting}>
+            Hello, {user?.user_name || 'User'}
+          </Text>
+          <Text style={styles.headerTitle}>Your Patients</Text>
+        </View>
+        <TouchableOpacity style={styles.addButton}>
+          <Ionicons name="add" size={24} color={AppColors.white} />
+        </TouchableOpacity>
+      </View>
 
-        <ThemedText>
-          {`Tap the Explore tab to learn more about what's included in this starter app.`}
-        </ThemedText>
-      </ThemedView>
-      <ThemedView style={styles.stepContainer}>
-        <ThemedText type="subtitle">Step 3: Get a fresh start</ThemedText>
-        <ThemedText>
-          {`When you're ready, run `}
-          <ThemedText type="defaultSemiBold">npm run reset-project</ThemedText> to get a fresh{' '}
-          <ThemedText type="defaultSemiBold">app</ThemedText> directory. This will move the current{' '}
-          <ThemedText type="defaultSemiBold">app</ThemedText> to{' '}
-          <ThemedText type="defaultSemiBold">app-example</ThemedText>.
-        </ThemedText>
-      </ThemedView>
-    </ParallaxScrollView>
+      {/* Patient List */}
+      <FlatList
+        data={patients}
+        keyExtractor={(item) => item.id.toString()}
+        renderItem={renderPatientCard}
+        contentContainerStyle={styles.listContent}
+        showsVerticalScrollIndicator={false}
+        refreshControl={
+          <RefreshControl
+            refreshing={isRefreshing}
+            onRefresh={handleRefresh}
+            tintColor={AppColors.primary}
+          />
+        }
+        ListEmptyComponent={
+          <View style={styles.emptyContainer}>
+            <Ionicons name="people-outline" size={64} color={AppColors.textMuted} />
+            <Text style={styles.emptyTitle}>No patients yet</Text>
+            <Text style={styles.emptyText}>
+              Add your first patient to start monitoring
+            </Text>
+          </View>
+        }
+      />
+    </SafeAreaView>
   );
 }
 
 const styles = StyleSheet.create({
-  titleContainer: {
+  container: {
+    flex: 1,
+    backgroundColor: AppColors.surface,
+  },
+  header: {
+    flexDirection: 'row',
+    justifyContent: 'space-between',
+    alignItems: 'center',
+    paddingHorizontal: Spacing.lg,
+    paddingVertical: Spacing.md,
+    backgroundColor: AppColors.background,
+    borderBottomWidth: 1,
+    borderBottomColor: AppColors.border,
+  },
+  greeting: {
+    fontSize: FontSizes.sm,
+    color: AppColors.textSecondary,
+  },
+  headerTitle: {
+    fontSize: FontSizes.xl,
+    fontWeight: '700',
+    color: AppColors.textPrimary,
+  },
+  addButton: {
+    width: 44,
+    height: 44,
+    borderRadius: BorderRadius.full,
+    backgroundColor: AppColors.primary,
+    justifyContent: 'center',
+    alignItems: 'center',
+  },
+  listContent: {
+    padding: Spacing.md,
+  },
+  patientCard: {
+    backgroundColor: AppColors.background,
+    borderRadius: BorderRadius.lg,
+    padding: Spacing.md,
+    marginBottom: Spacing.md,
+    shadowColor: '#000',
+    shadowOffset: { width: 0, height: 2 },
+    shadowOpacity: 0.05,
+    shadowRadius: 4,
+    elevation: 2,
+  },
+  patientInfo: {
     flexDirection: 'row',
     alignItems: 'center',
-    gap: 8,
+    marginBottom: Spacing.md,
   },
-  stepContainer: {
-    gap: 8,
-    marginBottom: 8,
+  avatarContainer: {
+    width: 56,
+    height: 56,
+    borderRadius: BorderRadius.full,
+    backgroundColor: AppColors.primaryLight,
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginRight: Spacing.md,
   },
-  reactLogo: {
-    height: 178,
-    width: 290,
-    bottom: 0,
-    left: 0,
+  avatarText: {
+    fontSize: FontSizes.xl,
+    fontWeight: '600',
+    color: AppColors.white,
+  },
+  statusIndicator: {
     position: 'absolute',
+    bottom: 2,
+    right: 2,
+    width: 14,
+    height: 14,
+    borderRadius: BorderRadius.full,
+    borderWidth: 2,
+    borderColor: AppColors.background,
+  },
+  online: {
+    backgroundColor: AppColors.online,
+  },
+  offline: {
+    backgroundColor: AppColors.offline,
+  },
+  patientDetails: {
+    flex: 1,
+  },
+  patientName: {
+    fontSize: FontSizes.lg,
+    fontWeight: '600',
+    color: AppColors.textPrimary,
+  },
+  patientRelationship: {
+    fontSize: FontSizes.sm,
+    color: AppColors.textSecondary,
+    marginTop: 2,
+  },
+  lastActivity: {
+    fontSize: FontSizes.xs,
+    color: AppColors.textMuted,
+    marginTop: 4,
+  },
+  healthStats: {
+    flexDirection: 'row',
+    justifyContent: 'space-around',
+    paddingTop: Spacing.md,
+    borderTopWidth: 1,
+    borderTopColor: AppColors.border,
+  },
+  statItem: {
+    alignItems: 'center',
+  },
+  statValue: {
+    fontSize: FontSizes.base,
+    fontWeight: '600',
+    color: AppColors.textPrimary,
+    marginTop: Spacing.xs,
+  },
+  statLabel: {
+    fontSize: FontSizes.xs,
+    color: AppColors.textMuted,
+  },
+  chevron: {
+    position: 'absolute',
+    top: Spacing.md,
+    right: Spacing.md,
+  },
+  emptyContainer: {
+    flex: 1,
+    justifyContent: 'center',
+    alignItems: 'center',
+    paddingTop: Spacing.xxl * 2,
+  },
+  emptyTitle: {
+    fontSize: FontSizes.lg,
+    fontWeight: '600',
+    color: AppColors.textPrimary,
+    marginTop: Spacing.md,
+  },
+  emptyText: {
+    fontSize: FontSizes.base,
+    color: AppColors.textSecondary,
+    textAlign: 'center',
+    marginTop: Spacing.xs,
   },
 });
diff --git a/app/(tabs)/profile.tsx b/app/(tabs)/profile.tsx
new file mode 100644
index 0000000..095a28a
--- /dev/null
+++ b/app/(tabs)/profile.tsx
@@ -0,0 +1,314 @@
+import React from 'react';
+import {
+  View,
+  Text,
+  StyleSheet,
+  ScrollView,
+  TouchableOpacity,
+  Alert,
+} from 'react-native';
+import { router } from 'expo-router';
+import { Ionicons } from '@expo/vector-icons';
+import { SafeAreaView } from 'react-native-safe-area-context';
+import { useAuth } from '@/contexts/AuthContext';
+import { AppColors, BorderRadius, FontSizes, Spacing } from '@/constants/theme';
+
+interface MenuItemProps {
+  icon: keyof typeof Ionicons.glyphMap;
+  iconColor?: string;
+  iconBgColor?: string;
+  title: string;
+  subtitle?: string;
+  onPress?: () => void;
+  showChevron?: boolean;
+}
+
+function MenuItem({
+  icon,
+  iconColor = AppColors.primary,
+  iconBgColor = '#DBEAFE',
+  title,
+  subtitle,
+  onPress,
+  showChevron = true,
+}: MenuItemProps) {
+  return (
+    <TouchableOpacity style={styles.menuItem} onPress={onPress}>
+      <View style={[styles.menuIconContainer, { backgroundColor: iconBgColor }]}>
+        <Ionicons name={icon} size={20} color={iconColor} />
+      </View>
+      <View style={styles.menuTextContainer}>
+        <Text style={styles.menuTitle}>{title}</Text>
+        {subtitle && <Text style={styles.menuSubtitle}>{subtitle}</Text>}
+      </View>
+      {showChevron && (
+        <Ionicons name="chevron-forward" size={20} color={AppColors.textMuted} />
+      )}
+    </TouchableOpacity>
+  );
+}
+
+export default function ProfileScreen() {
+  const { user, logout } = useAuth();
+
+  const handleLogout = () => {
+    Alert.alert(
+      'Logout',
+      'Are you sure you want to logout?',
+      [
+        { text: 'Cancel', style: 'cancel' },
+        {
+          text: 'Logout',
+          style: 'destructive',
+          onPress: async () => {
+            await logout();
+            router.replace('/(auth)/login');
+          },
+        },
+      ],
+      { cancelable: true }
+    );
+  };
+
+  return (
+    <SafeAreaView style={styles.container} edges={['top']}>
+      <ScrollView showsVerticalScrollIndicator={false}>
+        {/* Header */}
+        <View style={styles.header}>
+          <Text style={styles.headerTitle}>Profile</Text>
+        </View>
+
+        {/* User Info */}
+        <View style={styles.userCard}>
+          <View style={styles.avatarContainer}>
+            <Text style={styles.avatarText}>
+              {user?.user_name?.charAt(0).toUpperCase() || 'U'}
+            </Text>
+          </View>
+          <View style={styles.userInfo}>
+            <Text style={styles.userName}>{user?.user_name || 'User'}</Text>
+            <Text style={styles.userRole}>
+              Role: {user?.max_role === 2 ? 'Admin' : 'User'}
+            </Text>
+          </View>
+          <TouchableOpacity style={styles.editButton}>
+            <Ionicons name="pencil" size={18} color={AppColors.primary} />
+          </TouchableOpacity>
+        </View>
+
+        {/* Menu Sections */}
+        <View style={styles.section}>
+          <Text style={styles.sectionTitle}>Account</Text>
+          <View style={styles.menuCard}>
+            <MenuItem
+              icon="person-outline"
+              title="Edit Profile"
+              subtitle="Update your personal information"
+            />
+            <View style={styles.menuDivider} />
+            <MenuItem
+              icon="notifications-outline"
+              iconBgColor="#FEF3C7"
+              iconColor={AppColors.warning}
+              title="Notifications"
+              subtitle="Manage notification preferences"
+            />
+            <View style={styles.menuDivider} />
+            <MenuItem
+              icon="shield-checkmark-outline"
+              iconBgColor="#D1FAE5"
+              iconColor={AppColors.success}
+              title="Privacy & Security"
+              subtitle="Password, 2FA, data"
+            />
+          </View>
+        </View>
+
+        <View style={styles.section}>
+          <Text style={styles.sectionTitle}>Subscription</Text>
+          <View style={styles.menuCard}>
+            <MenuItem
+              icon="diamond-outline"
+              iconBgColor="#F3E8FF"
+              iconColor="#9333EA"
+              title="WellNuo Pro"
+              subtitle="Upgrade for premium features"
+            />
+            <View style={styles.menuDivider} />
+            <MenuItem
+              icon="card-outline"
+              title="Payment Methods"
+              subtitle="Manage your payment options"
+            />
+          </View>
+        </View>
+
+        <View style={styles.section}>
+          <Text style={styles.sectionTitle}>Support</Text>
+          <View style={styles.menuCard}>
+            <MenuItem
+              icon="help-circle-outline"
+              title="Help Center"
+              subtitle="FAQs and guides"
+            />
+            <View style={styles.menuDivider} />
+            <MenuItem
+              icon="chatbubble-outline"
+              title="Contact Support"
+              subtitle="Get help from our team"
+            />
+            <View style={styles.menuDivider} />
+            <MenuItem
+              icon="document-text-outline"
+              title="Terms of Service"
+            />
+            <View style={styles.menuDivider} />
+            <MenuItem
+              icon="shield-outline"
+              title="Privacy Policy"
+            />
+          </View>
+        </View>
+
+        {/* Logout Button */}
+        <View style={styles.section}>
+          <TouchableOpacity style={styles.logoutButton} onPress={handleLogout}>
+            <Ionicons name="log-out-outline" size={20} color={AppColors.error} />
+            <Text style={styles.logoutText}>Logout</Text>
+          </TouchableOpacity>
+        </View>
+
+        {/* Version */}
+        <Text style={styles.version}>WellNuo v1.0.0</Text>
+      </ScrollView>
+    </SafeAreaView>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    backgroundColor: AppColors.surface,
+  },
+  header: {
+    paddingHorizontal: Spacing.lg,
+    paddingVertical: Spacing.md,
+    backgroundColor: AppColors.background,
+    borderBottomWidth: 1,
+    borderBottomColor: AppColors.border,
+  },
+  headerTitle: {
+    fontSize: FontSizes.xl,
+    fontWeight: '700',
+    color: AppColors.textPrimary,
+  },
+  userCard: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    backgroundColor: AppColors.background,
+    padding: Spacing.lg,
+    marginBottom: Spacing.md,
+  },
+  avatarContainer: {
+    width: 64,
+    height: 64,
+    borderRadius: BorderRadius.full,
+    backgroundColor: AppColors.primary,
+    justifyContent: 'center',
+    alignItems: 'center',
+  },
+  avatarText: {
+    fontSize: FontSizes['2xl'],
+    fontWeight: '600',
+    color: AppColors.white,
+  },
+  userInfo: {
+    flex: 1,
+    marginLeft: Spacing.md,
+  },
+  userName: {
+    fontSize: FontSizes.lg,
+    fontWeight: '600',
+    color: AppColors.textPrimary,
+  },
+  userRole: {
+    fontSize: FontSizes.sm,
+    color: AppColors.textSecondary,
+    marginTop: Spacing.xs,
+  },
+  editButton: {
+    width: 40,
+    height: 40,
+    borderRadius: BorderRadius.full,
+    backgroundColor: AppColors.surface,
+    justifyContent: 'center',
+    alignItems: 'center',
+  },
+  section: {
+    marginBottom: Spacing.md,
+  },
+  sectionTitle: {
+    fontSize: FontSizes.sm,
+    fontWeight: '600',
+    color: AppColors.textSecondary,
+    paddingHorizontal: Spacing.lg,
+    paddingVertical: Spacing.sm,
+    textTransform: 'uppercase',
+  },
+  menuCard: {
+    backgroundColor: AppColors.background,
+  },
+  menuItem: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    paddingVertical: Spacing.md,
+    paddingHorizontal: Spacing.lg,
+  },
+  menuIconContainer: {
+    width: 36,
+    height: 36,
+    borderRadius: BorderRadius.md,
+    justifyContent: 'center',
+    alignItems: 'center',
+  },
+  menuTextContainer: {
+    flex: 1,
+    marginLeft: Spacing.md,
+  },
+  menuTitle: {
+    fontSize: FontSizes.base,
+    fontWeight: '500',
+    color: AppColors.textPrimary,
+  },
+  menuSubtitle: {
+    fontSize: FontSizes.xs,
+    color: AppColors.textMuted,
+    marginTop: 2,
+  },
+  menuDivider: {
+    height: 1,
+    backgroundColor: AppColors.border,
+    marginLeft: Spacing.lg + 36 + Spacing.md,
+  },
+  logoutButton: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    justifyContent: 'center',
+    backgroundColor: AppColors.background,
+    paddingVertical: Spacing.md,
+    marginHorizontal: Spacing.lg,
+    borderRadius: BorderRadius.lg,
+  },
+  logoutText: {
+    fontSize: FontSizes.base,
+    fontWeight: '600',
+    color: AppColors.error,
+    marginLeft: Spacing.sm,
+  },
+  version: {
+    textAlign: 'center',
+    fontSize: FontSizes.xs,
+    color: AppColors.textMuted,
+    paddingVertical: Spacing.xl,
+  },
+});
diff --git a/app/_layout.tsx b/app/_layout.tsx
index f518c9b..6824850 100644
--- a/app/_layout.tsx
+++ b/app/_layout.tsx
@@ -1,24 +1,60 @@
+import { useEffect } from 'react';
 import { DarkTheme, DefaultTheme, ThemeProvider } from '@react-navigation/native';
-import { Stack } from 'expo-router';
+import { Stack, router, useSegments } from 'expo-router';
 import { StatusBar } from 'expo-status-bar';
+import * as SplashScreen from 'expo-splash-screen';
 import 'react-native-reanimated';
 
 import { useColorScheme } from '@/hooks/use-color-scheme';
+import { AuthProvider, useAuth } from '@/contexts/AuthContext';
+import { LoadingSpinner } from '@/components/ui/LoadingSpinner';
 
-export const unstable_settings = {
-  anchor: '(tabs)',
-};
+// Prevent auto-hiding splash screen
+SplashScreen.preventAutoHideAsync();
 
-export default function RootLayout() {
+function RootLayoutNav() {
   const colorScheme = useColorScheme();
+  const { isAuthenticated, isLoading } = useAuth();
+  const segments = useSegments();
+
+  useEffect(() => {
+    if (isLoading) return;
+
+    // Hide splash screen once we know auth state
+    SplashScreen.hideAsync();
+
+    const inAuthGroup = segments[0] === '(auth)';
+
+    if (!isAuthenticated && !inAuthGroup) {
+      // Redirect to login if not authenticated
+      router.replace('/(auth)/login');
+    } else if (isAuthenticated && inAuthGroup) {
+      // Redirect to main app if authenticated
+      router.replace('/(tabs)');
+    }
+  }, [isAuthenticated, isLoading, segments]);
+
+  if (isLoading) {
+    return <LoadingSpinner fullScreen message="Loading..." />;
+  }
 
   return (
     <ThemeProvider value={colorScheme === 'dark' ? DarkTheme : DefaultTheme}>
-      <Stack>
-        <Stack.Screen name="(tabs)" options={{ headerShown: false }} />
+      <Stack screenOptions={{ headerShown: false }}>
+        <Stack.Screen name="(auth)" />
+        <Stack.Screen name="(tabs)" />
+        <Stack.Screen name="patients" />
         <Stack.Screen name="modal" options={{ presentation: 'modal', title: 'Modal' }} />
       </Stack>
       <StatusBar style="auto" />
     </ThemeProvider>
   );
 }
+
+export default function RootLayout() {
+  return (
+    <AuthProvider>
+      <RootLayoutNav />
+    </AuthProvider>
+  );
+}
diff --git a/app/patients/[id]/index.tsx b/app/patients/[id]/index.tsx
new file mode 100644
index 0000000..b1eef70
--- /dev/null
+++ b/app/patients/[id]/index.tsx
@@ -0,0 +1,371 @@
+import React, { useState, useEffect, useCallback } from 'react';
+import {
+  View,
+  Text,
+  StyleSheet,
+  ScrollView,
+  TouchableOpacity,
+  RefreshControl,
+} from 'react-native';
+import { useLocalSearchParams, router } from 'expo-router';
+import { Ionicons } from '@expo/vector-icons';
+import { SafeAreaView } from 'react-native-safe-area-context';
+import { api } from '@/services/api';
+import { LoadingSpinner } from '@/components/ui/LoadingSpinner';
+import { FullScreenError } from '@/components/ui/ErrorMessage';
+import { Button } from '@/components/ui/Button';
+import { AppColors, BorderRadius, FontSizes, Spacing } from '@/constants/theme';
+import type { Patient } from '@/types';
+
+export default function PatientDashboardScreen() {
+  const { id } = useLocalSearchParams<{ id: string }>();
+  const [patient, setPatient] = useState<Patient | null>(null);
+  const [isLoading, setIsLoading] = useState(true);
+  const [isRefreshing, setIsRefreshing] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const loadPatient = useCallback(async (showLoading = true) => {
+    if (!id) return;
+
+    if (showLoading) setIsLoading(true);
+    setError(null);
+
+    try {
+      const response = await api.getPatient(parseInt(id, 10));
+
+      if (response.ok && response.data) {
+        setPatient(response.data);
+      } else {
+        setError(response.error?.message || 'Failed to load patient');
+      }
+    } catch (err) {
+      setError(err instanceof Error ? err.message : 'An error occurred');
+    } finally {
+      setIsLoading(false);
+      setIsRefreshing(false);
+    }
+  }, [id]);
+
+  useEffect(() => {
+    loadPatient();
+  }, [loadPatient]);
+
+  const handleRefresh = useCallback(() => {
+    setIsRefreshing(true);
+    loadPatient(false);
+  }, [loadPatient]);
+
+  const handleChatPress = () => {
+    router.push('/(tabs)/chat');
+  };
+
+  if (isLoading) {
+    return <LoadingSpinner fullScreen message="Loading patient data..." />;
+  }
+
+  if (error || !patient) {
+    return (
+      <FullScreenError
+        message={error || 'Patient not found'}
+        onRetry={() => loadPatient()}
+      />
+    );
+  }
+
+  return (
+    <SafeAreaView style={styles.container} edges={['top']}>
+      {/* Header */}
+      <View style={styles.header}>
+        <TouchableOpacity
+          style={styles.backButton}
+          onPress={() => router.back()}
+        >
+          <Ionicons name="arrow-back" size={24} color={AppColors.textPrimary} />
+        </TouchableOpacity>
+        <Text style={styles.headerTitle}>{patient.name}</Text>
+        <TouchableOpacity style={styles.menuButton}>
+          <Ionicons name="ellipsis-vertical" size={24} color={AppColors.textPrimary} />
+        </TouchableOpacity>
+      </View>
+
+      <ScrollView
+        style={styles.content}
+        showsVerticalScrollIndicator={false}
+        refreshControl={
+          <RefreshControl
+            refreshing={isRefreshing}
+            onRefresh={handleRefresh}
+            tintColor={AppColors.primary}
+          />
+        }
+      >
+        {/* Patient Info Card */}
+        <View style={styles.infoCard}>
+          <View style={styles.avatarContainer}>
+            <Text style={styles.avatarText}>
+              {patient.name.charAt(0).toUpperCase()}
+            </Text>
+            <View
+              style={[
+                styles.statusBadge,
+                patient.status === 'online' ? styles.onlineBadge : styles.offlineBadge,
+              ]}
+            >
+              <Text style={styles.statusText}>
+                {patient.status === 'online' ? 'Online' : 'Offline'}
+              </Text>
+            </View>
+          </View>
+
+          <Text style={styles.patientName}>{patient.name}</Text>
+          <Text style={styles.relationship}>{patient.relationship}</Text>
+          <Text style={styles.lastSeen}>
+            Last activity: {patient.last_activity}
+          </Text>
+        </View>
+
+        {/* Health Stats */}
+        <View style={styles.section}>
+          <Text style={styles.sectionTitle}>Health Overview</Text>
+
+          <View style={styles.statsGrid}>
+            <View style={styles.statCard}>
+              <View style={[styles.statIcon, { backgroundColor: '#FEE2E2' }]}>
+                <Ionicons name="heart" size={24} color={AppColors.error} />
+              </View>
+              <Text style={styles.statValue}>
+                {patient.health_data?.heart_rate || '--'}
+              </Text>
+              <Text style={styles.statLabel}>Heart Rate</Text>
+              <Text style={styles.statUnit}>BPM</Text>
+            </View>
+
+            <View style={styles.statCard}>
+              <View style={[styles.statIcon, { backgroundColor: '#DBEAFE' }]}>
+                <Ionicons name="footsteps" size={24} color={AppColors.primary} />
+              </View>
+              <Text style={styles.statValue}>
+                {patient.health_data?.steps?.toLocaleString() || '--'}
+              </Text>
+              <Text style={styles.statLabel}>Steps Today</Text>
+              <Text style={styles.statUnit}>steps</Text>
+            </View>
+
+            <View style={styles.statCard}>
+              <View style={[styles.statIcon, { backgroundColor: '#E0E7FF' }]}>
+                <Ionicons name="moon" size={24} color={AppColors.primaryDark} />
+              </View>
+              <Text style={styles.statValue}>
+                {patient.health_data?.sleep_hours || '--'}
+              </Text>
+              <Text style={styles.statLabel}>Sleep</Text>
+              <Text style={styles.statUnit}>hours</Text>
+            </View>
+          </View>
+        </View>
+
+        {/* Quick Actions */}
+        <View style={styles.section}>
+          <Text style={styles.sectionTitle}>Quick Actions</Text>
+
+          <View style={styles.actionsGrid}>
+            <TouchableOpacity style={styles.actionCard} onPress={handleChatPress}>
+              <View style={[styles.actionIcon, { backgroundColor: '#D1FAE5' }]}>
+                <Ionicons name="chatbubble-ellipses" size={24} color={AppColors.success} />
+              </View>
+              <Text style={styles.actionLabel}>Chat with Julia</Text>
+            </TouchableOpacity>
+
+            <TouchableOpacity style={styles.actionCard}>
+              <View style={[styles.actionIcon, { backgroundColor: '#FEF3C7' }]}>
+                <Ionicons name="notifications" size={24} color={AppColors.warning} />
+              </View>
+              <Text style={styles.actionLabel}>Set Reminder</Text>
+            </TouchableOpacity>
+
+            <TouchableOpacity style={styles.actionCard}>
+              <View style={[styles.actionIcon, { backgroundColor: '#DBEAFE' }]}>
+                <Ionicons name="call" size={24} color={AppColors.primary} />
+              </View>
+              <Text style={styles.actionLabel}>Video Call</Text>
+            </TouchableOpacity>
+
+            <TouchableOpacity style={styles.actionCard}>
+              <View style={[styles.actionIcon, { backgroundColor: '#F3E8FF' }]}>
+                <Ionicons name="medkit" size={24} color="#9333EA" />
+              </View>
+              <Text style={styles.actionLabel}>Medications</Text>
+            </TouchableOpacity>
+          </View>
+        </View>
+
+        {/* Chat with Julia Button */}
+        <View style={styles.chatButtonContainer}>
+          <Button
+            title="Chat with Julia AI"
+            onPress={handleChatPress}
+            fullWidth
+            size="lg"
+          />
+        </View>
+      </ScrollView>
+    </SafeAreaView>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    backgroundColor: AppColors.surface,
+  },
+  header: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    justifyContent: 'space-between',
+    paddingHorizontal: Spacing.md,
+    paddingVertical: Spacing.sm,
+    backgroundColor: AppColors.background,
+    borderBottomWidth: 1,
+    borderBottomColor: AppColors.border,
+  },
+  backButton: {
+    padding: Spacing.xs,
+  },
+  headerTitle: {
+    fontSize: FontSizes.lg,
+    fontWeight: '600',
+    color: AppColors.textPrimary,
+  },
+  menuButton: {
+    padding: Spacing.xs,
+  },
+  content: {
+    flex: 1,
+  },
+  infoCard: {
+    backgroundColor: AppColors.background,
+    padding: Spacing.xl,
+    alignItems: 'center',
+    marginBottom: Spacing.md,
+  },
+  avatarContainer: {
+    width: 100,
+    height: 100,
+    borderRadius: BorderRadius.full,
+    backgroundColor: AppColors.primaryLight,
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginBottom: Spacing.md,
+  },
+  avatarText: {
+    fontSize: FontSizes['3xl'],
+    fontWeight: '600',
+    color: AppColors.white,
+  },
+  statusBadge: {
+    position: 'absolute',
+    bottom: 0,
+    paddingHorizontal: Spacing.sm,
+    paddingVertical: Spacing.xs,
+    borderRadius: BorderRadius.full,
+  },
+  onlineBadge: {
+    backgroundColor: AppColors.success,
+  },
+  offlineBadge: {
+    backgroundColor: AppColors.offline,
+  },
+  statusText: {
+    fontSize: FontSizes.xs,
+    fontWeight: '500',
+    color: AppColors.white,
+  },
+  patientName: {
+    fontSize: FontSizes['2xl'],
+    fontWeight: '700',
+    color: AppColors.textPrimary,
+  },
+  relationship: {
+    fontSize: FontSizes.base,
+    color: AppColors.textSecondary,
+    marginTop: Spacing.xs,
+  },
+  lastSeen: {
+    fontSize: FontSizes.sm,
+    color: AppColors.textMuted,
+    marginTop: Spacing.sm,
+  },
+  section: {
+    backgroundColor: AppColors.background,
+    padding: Spacing.lg,
+    marginBottom: Spacing.md,
+  },
+  sectionTitle: {
+    fontSize: FontSizes.lg,
+    fontWeight: '600',
+    color: AppColors.textPrimary,
+    marginBottom: Spacing.md,
+  },
+  statsGrid: {
+    flexDirection: 'row',
+    justifyContent: 'space-between',
+  },
+  statCard: {
+    flex: 1,
+    alignItems: 'center',
+    padding: Spacing.sm,
+  },
+  statIcon: {
+    width: 48,
+    height: 48,
+    borderRadius: BorderRadius.lg,
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginBottom: Spacing.sm,
+  },
+  statValue: {
+    fontSize: FontSizes.xl,
+    fontWeight: '700',
+    color: AppColors.textPrimary,
+  },
+  statLabel: {
+    fontSize: FontSizes.xs,
+    color: AppColors.textSecondary,
+    marginTop: Spacing.xs,
+  },
+  statUnit: {
+    fontSize: FontSizes.xs,
+    color: AppColors.textMuted,
+  },
+  actionsGrid: {
+    flexDirection: 'row',
+    flexWrap: 'wrap',
+    justifyContent: 'space-between',
+  },
+  actionCard: {
+    width: '48%',
+    backgroundColor: AppColors.surface,
+    borderRadius: BorderRadius.lg,
+    padding: Spacing.md,
+    alignItems: 'center',
+    marginBottom: Spacing.md,
+  },
+  actionIcon: {
+    width: 48,
+    height: 48,
+    borderRadius: BorderRadius.lg,
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginBottom: Spacing.sm,
+  },
+  actionLabel: {
+    fontSize: FontSizes.sm,
+    fontWeight: '500',
+    color: AppColors.textPrimary,
+    textAlign: 'center',
+  },
+  chatButtonContainer: {
+    padding: Spacing.lg,
+    paddingBottom: Spacing.xxl,
+  },
+});
diff --git a/app/patients/_layout.tsx b/app/patients/_layout.tsx
new file mode 100644
index 0000000..df580ec
--- /dev/null
+++ b/app/patients/_layout.tsx
@@ -0,0 +1,15 @@
+import { Stack } from 'expo-router';
+import { AppColors } from '@/constants/theme';
+
+export default function PatientsLayout() {
+  return (
+    <Stack
+      screenOptions={{
+        headerShown: false,
+        contentStyle: { backgroundColor: AppColors.background },
+      }}
+    >
+      <Stack.Screen name="[id]/index" />
+    </Stack>
+  );
+}
diff --git a/components/ui/Button.tsx b/components/ui/Button.tsx
new file mode 100644
index 0000000..ec8692b
--- /dev/null
+++ b/components/ui/Button.tsx
@@ -0,0 +1,137 @@
+import React from 'react';
+import {
+  TouchableOpacity,
+  Text,
+  StyleSheet,
+  ActivityIndicator,
+  type TouchableOpacityProps,
+  type ViewStyle,
+  type TextStyle,
+} from 'react-native';
+import { AppColors, BorderRadius, FontSizes, FontWeights, Spacing } from '@/constants/theme';
+
+interface ButtonProps extends TouchableOpacityProps {
+  title: string;
+  variant?: 'primary' | 'secondary' | 'outline' | 'ghost';
+  size?: 'sm' | 'md' | 'lg';
+  loading?: boolean;
+  fullWidth?: boolean;
+}
+
+export function Button({
+  title,
+  variant = 'primary',
+  size = 'md',
+  loading = false,
+  fullWidth = false,
+  disabled,
+  style,
+  ...props
+}: ButtonProps) {
+  const isDisabled = disabled || loading;
+
+  const buttonStyles: ViewStyle[] = [
+    styles.base,
+    styles[variant],
+    styles[`size_${size}`],
+    fullWidth && styles.fullWidth,
+    isDisabled && styles.disabled,
+    style as ViewStyle,
+  ];
+
+  const textStyles: TextStyle[] = [
+    styles.text,
+    styles[`text_${variant}`],
+    styles[`text_${size}`],
+    isDisabled && styles.textDisabled,
+  ];
+
+  return (
+    <TouchableOpacity
+      style={buttonStyles}
+      disabled={isDisabled}
+      activeOpacity={0.7}
+      {...props}
+    >
+      {loading ? (
+        <ActivityIndicator
+          color={variant === 'primary' ? AppColors.white : AppColors.primary}
+          size="small"
+        />
+      ) : (
+        <Text style={textStyles}>{title}</Text>
+      )}
+    </TouchableOpacity>
+  );
+}
+
+const styles = StyleSheet.create({
+  base: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    justifyContent: 'center',
+    borderRadius: BorderRadius.lg,
+  },
+  primary: {
+    backgroundColor: AppColors.primary,
+  },
+  secondary: {
+    backgroundColor: AppColors.surface,
+  },
+  outline: {
+    backgroundColor: 'transparent',
+    borderWidth: 1,
+    borderColor: AppColors.primary,
+  },
+  ghost: {
+    backgroundColor: 'transparent',
+  },
+  size_sm: {
+    paddingVertical: Spacing.sm,
+    paddingHorizontal: Spacing.md,
+    minHeight: 36,
+  },
+  size_md: {
+    paddingVertical: Spacing.sm + 4,
+    paddingHorizontal: Spacing.lg,
+    minHeight: 48,
+  },
+  size_lg: {
+    paddingVertical: Spacing.md,
+    paddingHorizontal: Spacing.xl,
+    minHeight: 56,
+  },
+  fullWidth: {
+    width: '100%',
+  },
+  disabled: {
+    opacity: 0.5,
+  },
+  text: {
+    fontWeight: FontWeights.semibold,
+  },
+  text_primary: {
+    color: AppColors.white,
+  },
+  text_secondary: {
+    color: AppColors.textPrimary,
+  },
+  text_outline: {
+    color: AppColors.primary,
+  },
+  text_ghost: {
+    color: AppColors.primary,
+  },
+  text_sm: {
+    fontSize: FontSizes.sm,
+  },
+  text_md: {
+    fontSize: FontSizes.base,
+  },
+  text_lg: {
+    fontSize: FontSizes.lg,
+  },
+  textDisabled: {
+    opacity: 0.7,
+  },
+});
diff --git a/components/ui/ErrorMessage.tsx b/components/ui/ErrorMessage.tsx
new file mode 100644
index 0000000..b2ef68b
--- /dev/null
+++ b/components/ui/ErrorMessage.tsx
@@ -0,0 +1,141 @@
+import React from 'react';
+import { View, Text, StyleSheet, TouchableOpacity } from 'react-native';
+import { Ionicons } from '@expo/vector-icons';
+import { AppColors, BorderRadius, FontSizes, Spacing } from '@/constants/theme';
+
+interface ErrorMessageProps {
+  message: string;
+  onRetry?: () => void;
+  onDismiss?: () => void;
+}
+
+export function ErrorMessage({ message, onRetry, onDismiss }: ErrorMessageProps) {
+  return (
+    <View style={styles.container}>
+      <View style={styles.content}>
+        <Ionicons name="alert-circle" size={24} color={AppColors.error} />
+        <Text style={styles.message}>{message}</Text>
+      </View>
+
+      <View style={styles.actions}>
+        {onRetry && (
+          <TouchableOpacity onPress={onRetry} style={styles.button}>
+            <Ionicons name="refresh" size={18} color={AppColors.primary} />
+            <Text style={styles.buttonText}>Retry</Text>
+          </TouchableOpacity>
+        )}
+        {onDismiss && (
+          <TouchableOpacity onPress={onDismiss} style={styles.dismissButton}>
+            <Ionicons name="close" size={18} color={AppColors.textMuted} />
+          </TouchableOpacity>
+        )}
+      </View>
+    </View>
+  );
+}
+
+interface FullScreenErrorProps {
+  title?: string;
+  message: string;
+  onRetry?: () => void;
+}
+
+export function FullScreenError({
+  title = 'Something went wrong',
+  message,
+  onRetry
+}: FullScreenErrorProps) {
+  return (
+    <View style={styles.fullScreenContainer}>
+      <Ionicons name="cloud-offline-outline" size={64} color={AppColors.textMuted} />
+      <Text style={styles.fullScreenTitle}>{title}</Text>
+      <Text style={styles.fullScreenMessage}>{message}</Text>
+
+      {onRetry && (
+        <TouchableOpacity onPress={onRetry} style={styles.retryButton}>
+          <Ionicons name="refresh" size={20} color={AppColors.white} />
+          <Text style={styles.retryButtonText}>Try Again</Text>
+        </TouchableOpacity>
+      )}
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    backgroundColor: '#FEE2E2',
+    borderRadius: BorderRadius.lg,
+    padding: Spacing.md,
+    flexDirection: 'row',
+    alignItems: 'center',
+    justifyContent: 'space-between',
+    marginVertical: Spacing.sm,
+  },
+  content: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    flex: 1,
+  },
+  message: {
+    color: AppColors.error,
+    fontSize: FontSizes.sm,
+    marginLeft: Spacing.sm,
+    flex: 1,
+  },
+  actions: {
+    flexDirection: 'row',
+    alignItems: 'center',
+  },
+  button: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    paddingHorizontal: Spacing.sm,
+    paddingVertical: Spacing.xs,
+  },
+  buttonText: {
+    color: AppColors.primary,
+    fontSize: FontSizes.sm,
+    fontWeight: '500',
+    marginLeft: Spacing.xs,
+  },
+  dismissButton: {
+    padding: Spacing.xs,
+    marginLeft: Spacing.xs,
+  },
+  // Full Screen Error
+  fullScreenContainer: {
+    flex: 1,
+    justifyContent: 'center',
+    alignItems: 'center',
+    padding: Spacing.xl,
+    backgroundColor: AppColors.background,
+  },
+  fullScreenTitle: {
+    fontSize: FontSizes.xl,
+    fontWeight: '600',
+    color: AppColors.textPrimary,
+    marginTop: Spacing.lg,
+    textAlign: 'center',
+  },
+  fullScreenMessage: {
+    fontSize: FontSizes.base,
+    color: AppColors.textSecondary,
+    marginTop: Spacing.sm,
+    textAlign: 'center',
+  },
+  retryButton: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    backgroundColor: AppColors.primary,
+    paddingVertical: Spacing.sm + 4,
+    paddingHorizontal: Spacing.lg,
+    borderRadius: BorderRadius.lg,
+    marginTop: Spacing.xl,
+  },
+  retryButtonText: {
+    color: AppColors.white,
+    fontSize: FontSizes.base,
+    fontWeight: '600',
+    marginLeft: Spacing.sm,
+  },
+});
diff --git a/components/ui/Input.tsx b/components/ui/Input.tsx
new file mode 100644
index 0000000..4990deb
--- /dev/null
+++ b/components/ui/Input.tsx
@@ -0,0 +1,143 @@
+import React, { useState } from 'react';
+import {
+  View,
+  TextInput,
+  Text,
+  StyleSheet,
+  TouchableOpacity,
+  type TextInputProps,
+} from 'react-native';
+import { Ionicons } from '@expo/vector-icons';
+import { AppColors, BorderRadius, FontSizes, Spacing } from '@/constants/theme';
+
+interface InputProps extends TextInputProps {
+  label?: string;
+  error?: string;
+  leftIcon?: keyof typeof Ionicons.glyphMap;
+  rightIcon?: keyof typeof Ionicons.glyphMap;
+  onRightIconPress?: () => void;
+}
+
+export function Input({
+  label,
+  error,
+  leftIcon,
+  rightIcon,
+  onRightIconPress,
+  secureTextEntry,
+  style,
+  ...props
+}: InputProps) {
+  const [isPasswordVisible, setIsPasswordVisible] = useState(false);
+  const isPassword = secureTextEntry !== undefined;
+
+  const handleTogglePassword = () => {
+    setIsPasswordVisible(!isPasswordVisible);
+  };
+
+  return (
+    <View style={styles.container}>
+      {label && <Text style={styles.label}>{label}</Text>}
+
+      <View style={[styles.inputContainer, error && styles.inputError]}>
+        {leftIcon && (
+          <Ionicons
+            name={leftIcon}
+            size={20}
+            color={AppColors.textMuted}
+            style={styles.leftIcon}
+          />
+        )}
+
+        <TextInput
+          style={[
+            styles.input,
+            leftIcon && styles.inputWithLeftIcon,
+            (isPassword || rightIcon) && styles.inputWithRightIcon,
+            style,
+          ]}
+          placeholderTextColor={AppColors.textMuted}
+          secureTextEntry={isPassword && !isPasswordVisible}
+          {...props}
+        />
+
+        {isPassword && (
+          <TouchableOpacity
+            onPress={handleTogglePassword}
+            style={styles.rightIconButton}
+          >
+            <Ionicons
+              name={isPasswordVisible ? 'eye-off-outline' : 'eye-outline'}
+              size={20}
+              color={AppColors.textMuted}
+            />
+          </TouchableOpacity>
+        )}
+
+        {!isPassword && rightIcon && (
+          <TouchableOpacity
+            onPress={onRightIconPress}
+            style={styles.rightIconButton}
+            disabled={!onRightIconPress}
+          >
+            <Ionicons
+              name={rightIcon}
+              size={20}
+              color={AppColors.textMuted}
+            />
+          </TouchableOpacity>
+        )}
+      </View>
+
+      {error && <Text style={styles.errorText}>{error}</Text>}
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    marginBottom: Spacing.md,
+  },
+  label: {
+    fontSize: FontSizes.sm,
+    fontWeight: '500',
+    color: AppColors.textPrimary,
+    marginBottom: Spacing.xs,
+  },
+  inputContainer: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    backgroundColor: AppColors.surface,
+    borderRadius: BorderRadius.lg,
+    borderWidth: 1,
+    borderColor: AppColors.border,
+  },
+  inputError: {
+    borderColor: AppColors.error,
+  },
+  input: {
+    flex: 1,
+    paddingVertical: Spacing.sm + 4,
+    paddingHorizontal: Spacing.md,
+    fontSize: FontSizes.base,
+    color: AppColors.textPrimary,
+  },
+  inputWithLeftIcon: {
+    paddingLeft: 0,
+  },
+  inputWithRightIcon: {
+    paddingRight: 0,
+  },
+  leftIcon: {
+    marginLeft: Spacing.md,
+    marginRight: Spacing.sm,
+  },
+  rightIconButton: {
+    padding: Spacing.md,
+  },
+  errorText: {
+    fontSize: FontSizes.xs,
+    color: AppColors.error,
+    marginTop: Spacing.xs,
+  },
+});
diff --git a/components/ui/LoadingSpinner.tsx b/components/ui/LoadingSpinner.tsx
new file mode 100644
index 0000000..a787e83
--- /dev/null
+++ b/components/ui/LoadingSpinner.tsx
@@ -0,0 +1,50 @@
+import React from 'react';
+import { View, ActivityIndicator, Text, StyleSheet } from 'react-native';
+import { AppColors, FontSizes, Spacing } from '@/constants/theme';
+
+interface LoadingSpinnerProps {
+  size?: 'small' | 'large';
+  color?: string;
+  message?: string;
+  fullScreen?: boolean;
+}
+
+export function LoadingSpinner({
+  size = 'large',
+  color = AppColors.primary,
+  message,
+  fullScreen = false,
+}: LoadingSpinnerProps) {
+  const content = (
+    <>
+      <ActivityIndicator size={size} color={color} />
+      {message && <Text style={styles.message}>{message}</Text>}
+    </>
+  );
+
+  if (fullScreen) {
+    return <View style={styles.fullScreen}>{content}</View>;
+  }
+
+  return <View style={styles.container}>{content}</View>;
+}
+
+const styles = StyleSheet.create({
+  container: {
+    alignItems: 'center',
+    justifyContent: 'center',
+    padding: Spacing.lg,
+  },
+  fullScreen: {
+    flex: 1,
+    alignItems: 'center',
+    justifyContent: 'center',
+    backgroundColor: AppColors.background,
+  },
+  message: {
+    marginTop: Spacing.md,
+    fontSize: FontSizes.base,
+    color: AppColors.textSecondary,
+    textAlign: 'center',
+  },
+});
diff --git a/constants/theme.ts b/constants/theme.ts
index f06facd..1c0e1d3 100644
--- a/constants/theme.ts
+++ b/constants/theme.ts
@@ -1,21 +1,55 @@
 /**
- * Below are the colors that are used in the app. The colors are defined in the light and dark mode.
- * There are many other ways to style your app. For example, [Nativewind](https://www.nativewind.dev/), [Tamagui](https://tamagui.dev/), [unistyles](https://reactnativeunistyles.vercel.app), etc.
+ * WellNuo Theme Configuration
+ * Colors and typography based on design system
  */
 
 import { Platform } from 'react-native';
 
-const tintColorLight = '#0a7ea4';
+// WellNuo Brand Colors
+export const AppColors = {
+  // Primary
+  primary: '#4A90D9',
+  primaryDark: '#2E5C8A',
+  primaryLight: '#6BA8E8',
+
+  // Status
+  success: '#5AC8A8',
+  warning: '#F5A623',
+  error: '#D0021B',
+
+  // Neutral
+  white: '#FFFFFF',
+  background: '#FFFFFF',
+  surface: '#F5F7FA',
+  border: '#E5E7EB',
+
+  // Text
+  textPrimary: '#333333',
+  textSecondary: '#666666',
+  textMuted: '#999999',
+  textLight: '#FFFFFF',
+
+  // Patient Status
+  online: '#5AC8A8',
+  offline: '#999999',
+};
+
+const tintColorLight = AppColors.primary;
 const tintColorDark = '#fff';
 
 export const Colors = {
   light: {
-    text: '#11181C',
-    background: '#fff',
+    text: AppColors.textPrimary,
+    background: AppColors.background,
     tint: tintColorLight,
     icon: '#687076',
     tabIconDefault: '#687076',
     tabIconSelected: tintColorLight,
+    surface: AppColors.surface,
+    border: AppColors.border,
+    primary: AppColors.primary,
+    error: AppColors.error,
+    success: AppColors.success,
   },
   dark: {
     text: '#ECEDEE',
@@ -24,18 +58,53 @@ export const Colors = {
     icon: '#9BA1A6',
     tabIconDefault: '#9BA1A6',
     tabIconSelected: tintColorDark,
+    surface: '#1E2022',
+    border: '#2D3135',
+    primary: AppColors.primaryLight,
+    error: '#FF6B6B',
+    success: '#6BD9B9',
   },
 };
 
+export const Spacing = {
+  xs: 4,
+  sm: 8,
+  md: 16,
+  lg: 24,
+  xl: 32,
+  xxl: 48,
+};
+
+export const BorderRadius = {
+  sm: 4,
+  md: 8,
+  lg: 12,
+  xl: 16,
+  full: 9999,
+};
+
+export const FontSizes = {
+  xs: 12,
+  sm: 14,
+  base: 16,
+  lg: 18,
+  xl: 20,
+  '2xl': 24,
+  '3xl': 30,
+};
+
+export const FontWeights = {
+  normal: '400' as const,
+  medium: '500' as const,
+  semibold: '600' as const,
+  bold: '700' as const,
+};
+
 export const Fonts = Platform.select({
   ios: {
-    /** iOS `UIFontDescriptorSystemDesignDefault` */
     sans: 'system-ui',
-    /** iOS `UIFontDescriptorSystemDesignSerif` */
     serif: 'ui-serif',
-    /** iOS `UIFontDescriptorSystemDesignRounded` */
     rounded: 'ui-rounded',
-    /** iOS `UIFontDescriptorSystemDesignMonospaced` */
     mono: 'ui-monospace',
   },
   default: {
diff --git a/contexts/AuthContext.tsx b/contexts/AuthContext.tsx
new file mode 100644
index 0000000..09efa57
--- /dev/null
+++ b/contexts/AuthContext.tsx
@@ -0,0 +1,136 @@
+import React, { createContext, useContext, useState, useEffect, useCallback, type ReactNode } from 'react';
+import { api } from '@/services/api';
+import type { User, LoginCredentials, ApiError } from '@/types';
+
+interface AuthState {
+  user: User | null;
+  isLoading: boolean;
+  isAuthenticated: boolean;
+  error: ApiError | null;
+}
+
+interface AuthContextType extends AuthState {
+  login: (credentials: LoginCredentials) => Promise<boolean>;
+  logout: () => Promise<void>;
+  clearError: () => void;
+}
+
+const AuthContext = createContext<AuthContextType | null>(null);
+
+export function AuthProvider({ children }: { children: ReactNode }) {
+  const [state, setState] = useState<AuthState>({
+    user: null,
+    isLoading: true,
+    isAuthenticated: false,
+    error: null,
+  });
+
+  // Check authentication on mount
+  useEffect(() => {
+    checkAuth();
+  }, []);
+
+  const checkAuth = async () => {
+    try {
+      const isAuth = await api.isAuthenticated();
+      if (isAuth) {
+        const user = await api.getStoredUser();
+        setState({
+          user,
+          isLoading: false,
+          isAuthenticated: !!user,
+          error: null,
+        });
+      } else {
+        setState({
+          user: null,
+          isLoading: false,
+          isAuthenticated: false,
+          error: null,
+        });
+      }
+    } catch (error) {
+      setState({
+        user: null,
+        isLoading: false,
+        isAuthenticated: false,
+        error: { message: 'Failed to check authentication' },
+      });
+    }
+  };
+
+  const login = useCallback(async (credentials: LoginCredentials): Promise<boolean> => {
+    setState((prev) => ({ ...prev, isLoading: true, error: null }));
+
+    try {
+      const response = await api.login(credentials.username, credentials.password);
+
+      if (response.ok && response.data) {
+        const user: User = {
+          user_id: response.data.user_id,
+          user_name: credentials.username,
+          max_role: response.data.max_role,
+          privileges: response.data.privileges,
+        };
+
+        setState({
+          user,
+          isLoading: false,
+          isAuthenticated: true,
+          error: null,
+        });
+
+        return true;
+      }
+
+      setState((prev) => ({
+        ...prev,
+        isLoading: false,
+        error: response.error || { message: 'Login failed' },
+      }));
+
+      return false;
+    } catch (error) {
+      setState((prev) => ({
+        ...prev,
+        isLoading: false,
+        error: { message: error instanceof Error ? error.message : 'Login failed' },
+      }));
+
+      return false;
+    }
+  }, []);
+
+  const logout = useCallback(async () => {
+    setState((prev) => ({ ...prev, isLoading: true }));
+
+    try {
+      await api.logout();
+    } finally {
+      setState({
+        user: null,
+        isLoading: false,
+        isAuthenticated: false,
+        error: null,
+      });
+    }
+  }, []);
+
+  const clearError = useCallback(() => {
+    setState((prev) => ({ ...prev, error: null }));
+  }, []);
+
+  return (
+    <AuthContext.Provider value={{ ...state, login, logout, clearError }}>
+      {children}
+    </AuthContext.Provider>
+  );
+}
+
+export function useAuth() {
+  const context = useContext(AuthContext);
+  if (!context) {
+    throw new Error('useAuth must be used within an AuthProvider');
+  }
+  return context;
+}
diff --git a/package-lock.json b/package-lock.json
index 5d29d40..20857bb 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -19,6 +19,7 @@
         "expo-image": "~3.0.11",
         "expo-linking": "~8.0.10",
         "expo-router": "~6.0.19",
+        "expo-secure-store": "^15.0.8",
         "expo-splash-screen": "~31.0.12",
         "expo-status-bar": "~3.0.9",
         "expo-symbols": "~1.0.8",
@@ -38,6 +39,7 @@
         "@types/react": "~19.1.0",
         "eslint": "^9.25.0",
         "eslint-config-expo": "~10.0.0",
+        "playwright": "^1.57.0",
         "typescript": "~5.9.2"
       }
     },
@@ -6443,6 +6445,15 @@
         "node": ">=10"
       }
     },
+    "node_modules/expo-secure-store": {
+      "version": "15.0.8",
+      "resolved": "https://registry.npmjs.org/expo-secure-store/-/expo-secure-store-15.0.8.tgz",
+      "integrity": "sha512-lHnzvRajBu4u+P99+0GEMijQMFCOYpWRO4dWsXSuMt77+THPIGjzNvVKrGSl6mMrLsfVaKL8BpwYZLGlgA+zAw==",
+      "license": "MIT",
+      "peerDependencies": {
+        "expo": "*"
+      }
+    },
     "node_modules/expo-server": {
       "version": "1.0.5",
       "resolved": "https://registry.npmjs.org/expo-server/-/expo-server-1.0.5.tgz",
@@ -9856,6 +9867,53 @@
         "node": ">= 6"
       }
     },
+    "node_modules/playwright": {
+      "version": "1.57.0",
+      "resolved": "https://registry.npmjs.org/playwright/-/playwright-1.57.0.tgz",
+      "integrity": "sha512-ilYQj1s8sr2ppEJ2YVadYBN0Mb3mdo9J0wQ+UuDhzYqURwSoW4n1Xs5vs7ORwgDGmyEh33tRMeS8KhdkMoLXQw==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "dependencies": {
+        "playwright-core": "1.57.0"
+      },
+      "bin": {
+        "playwright": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      },
+      "optionalDependencies": {
+        "fsevents": "2.3.2"
+      }
+    },
+    "node_modules/playwright-core": {
+      "version": "1.57.0",
+      "resolved": "https://registry.npmjs.org/playwright-core/-/playwright-core-1.57.0.tgz",
+      "integrity": "sha512-agTcKlMw/mjBWOnD6kFZttAAGHgi/Nw0CZ2o6JqWSbMlI219lAFLZZCyqByTsvVAJq5XA5H8cA6PrvBRpBWEuQ==",
+      "dev": true,
+      "license": "Apache-2.0",
+      "bin": {
+        "playwright-core": "cli.js"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
+    "node_modules/playwright/node_modules/fsevents": {
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
+      "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
+      "dev": true,
+      "hasInstallScript": true,
+      "license": "MIT",
+      "optional": true,
+      "os": [
+        "darwin"
+      ],
+      "engines": {
+        "node": "^8.16.0 || ^10.6.0 || >=11.0.0"
+      }
+    },
     "node_modules/plist": {
       "version": "3.1.0",
       "resolved": "https://registry.npmjs.org/plist/-/plist-3.1.0.tgz",
diff --git a/package.json b/package.json
index 92cbc93..cd6ea60 100644
--- a/package.json
+++ b/package.json
@@ -22,6 +22,7 @@
     "expo-image": "~3.0.11",
     "expo-linking": "~8.0.10",
     "expo-router": "~6.0.19",
+    "expo-secure-store": "^15.0.8",
     "expo-splash-screen": "~31.0.12",
     "expo-status-bar": "~3.0.9",
     "expo-symbols": "~1.0.8",
@@ -31,17 +32,18 @@
     "react-dom": "19.1.0",
     "react-native": "0.81.5",
     "react-native-gesture-handler": "~2.28.0",
-    "react-native-worklets": "0.5.1",
     "react-native-reanimated": "~4.1.1",
     "react-native-safe-area-context": "~5.6.0",
     "react-native-screens": "~4.16.0",
-    "react-native-web": "~0.21.0"
+    "react-native-web": "~0.21.0",
+    "react-native-worklets": "0.5.1"
   },
   "devDependencies": {
     "@types/react": "~19.1.0",
-    "typescript": "~5.9.2",
     "eslint": "^9.25.0",
-    "eslint-config-expo": "~10.0.0"
+    "eslint-config-expo": "~10.0.0",
+    "playwright": "^1.57.0",
+    "typescript": "~5.9.2"
   },
   "private": true
 }
diff --git a/services/api.ts b/services/api.ts
new file mode 100644
index 0000000..79bb774
--- /dev/null
+++ b/services/api.ts
@@ -0,0 +1,194 @@
+import * as SecureStore from 'expo-secure-store';
+import type { AuthResponse, ChatResponse, Patient, ApiResponse, ApiError } from '@/types';
+
+const API_BASE_URL = 'https://eluxnetworks.net/function/well-api/api';
+const CLIENT_ID = 'MA_001';
+
+class ApiService {
+  private async getToken(): Promise<string | null> {
+    try {
+      return await SecureStore.getItemAsync('accessToken');
+    } catch {
+      return null;
+    }
+  }
+
+  private async getUserName(): Promise<string | null> {
+    try {
+      return await SecureStore.getItemAsync('userName');
+    } catch {
+      return null;
+    }
+  }
+
+  private generateNonce(): string {
+    return Math.floor(Math.random() * 1000000).toString();
+  }
+
+  private async makeRequest<T>(params: Record<string, string>): Promise<ApiResponse<T>> {
+    try {
+      const formData = new URLSearchParams();
+      Object.entries(params).forEach(([key, value]) => {
+        formData.append(key, value);
+      });
+
+      const response = await fetch(API_BASE_URL, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/x-www-form-urlencoded',
+        },
+        body: formData.toString(),
+      });
+
+      const data = await response.json();
+
+      if (data.status === '200 OK' || data.ok === true) {
+        return { data: data as T, ok: true };
+      }
+
+      return {
+        ok: false,
+        error: {
+          message: data.message || data.error || 'Request failed',
+          status: response.status,
+        },
+      };
+    } catch (error) {
+      const apiError: ApiError = {
+        message: error instanceof Error ? error.message : 'Network error',
+        code: 'NETWORK_ERROR',
+      };
+      return { ok: false, error: apiError };
+    }
+  }
+
+  // Authentication
+  async login(username: string, password: string): Promise<ApiResponse<AuthResponse>> {
+    const response = await this.makeRequest<AuthResponse>({
+      function: 'credentials',
+      user_name: username,
+      ps: password,
+      clientId: CLIENT_ID,
+      nonce: this.generateNonce(),
+    });
+
+    if (response.ok && response.data) {
+      // Save credentials to SecureStore
+      await SecureStore.setItemAsync('accessToken', response.data.access_token);
+      await SecureStore.setItemAsync('userId', response.data.user_id.toString());
+      await SecureStore.setItemAsync('userName', username);
+      await SecureStore.setItemAsync('privileges', response.data.privileges);
+      await SecureStore.setItemAsync('maxRole', response.data.max_role.toString());
+    }
+
+    return response;
+  }
+
+  async logout(): Promise<void> {
+    await SecureStore.deleteItemAsync('accessToken');
+    await SecureStore.deleteItemAsync('userId');
+    await SecureStore.deleteItemAsync('userName');
+    await SecureStore.deleteItemAsync('privileges');
+    await SecureStore.deleteItemAsync('maxRole');
+  }
+
+  async isAuthenticated(): Promise<boolean> {
+    const token = await this.getToken();
+    return !!token;
+  }
+
+  // Get stored user info
+  async getStoredUser() {
+    try {
+      const userId = await SecureStore.getItemAsync('userId');
+      const userName = await SecureStore.getItemAsync('userName');
+      const privileges = await SecureStore.getItemAsync('privileges');
+      const maxRole = await SecureStore.getItemAsync('maxRole');
+
+      if (!userId || !userName) return null;
+
+      return {
+        user_id: parseInt(userId, 10),
+        user_name: userName,
+        privileges: privileges || '',
+        max_role: parseInt(maxRole || '0', 10),
+      };
+    } catch {
+      return null;
+    }
+  }
+
+  // Patients
+  async getPatients(): Promise<ApiResponse<{ patients: Patient[] }>> {
+    const token = await this.getToken();
+    if (!token) {
+      return { ok: false, error: { message: 'Not authenticated', code: 'UNAUTHORIZED' } };
+    }
+
+    // Note: Using mock data since get_patients API structure is not fully documented
+    // Replace with actual API call when available
+    const mockPatients: Patient[] = [
+      {
+        id: 1,
+        name: 'Julia Smith',
+        status: 'online',
+        relationship: 'Mother',
+        last_activity: '2 min ago',
+        health_data: {
+          heart_rate: 72,
+          steps: 3450,
+          sleep_hours: 7.5,
+        },
+      },
+      {
+        id: 2,
+        name: 'Robert Johnson',
+        status: 'offline',
+        relationship: 'Father',
+        last_activity: '1 hour ago',
+        health_data: {
+          heart_rate: 68,
+          steps: 2100,
+          sleep_hours: 6.8,
+        },
+      },
+    ];
+
+    return { data: { patients: mockPatients }, ok: true };
+  }
+
+  async getPatient(id: number): Promise<ApiResponse<Patient>> {
+    const response = await this.getPatients();
+    if (!response.ok || !response.data) {
+      return { ok: false, error: response.error };
+    }
+
+    const patient = response.data.patients.find((p) => p.id === id);
+    if (!patient) {
+      return { ok: false, error: { message: 'Patient not found', code: 'NOT_FOUND' } };
+    }
+
+    return { data: patient, ok: true };
+  }
+
+  // AI Chat
+  async sendMessage(question: string, deploymentId: string = '21'): Promise<ApiResponse<ChatResponse>> {
+    const token = await this.getToken();
+    const userName = await this.getUserName();
+
+    if (!token || !userName) {
+      return { ok: false, error: { message: 'Not authenticated', code: 'UNAUTHORIZED' } };
+    }
+
+    return this.makeRequest<ChatResponse>({
+      function: 'voice_ask',
+      clientId: CLIENT_ID,
+      user_name: userName,
+      token: token,
+      question: question,
+      deployment_id: deploymentId,
+    });
+  }
+}
+
+export const api = new ApiService();
diff --git a/types/index.ts b/types/index.ts
new file mode 100644
index 0000000..6d9ed9a
--- /dev/null
+++ b/types/index.ts
@@ -0,0 +1,70 @@
+// User & Auth Types
+export interface User {
+  user_id: number;
+  user_name: string;
+  max_role: number;
+  privileges: string;
+}
+
+export interface AuthResponse {
+  access_token: string;
+  privileges: string;
+  user_id: number;
+  max_role: number;
+  status: string;
+}
+
+export interface LoginCredentials {
+  username: string;
+  password: string;
+}
+
+// Patient Types
+export interface Patient {
+  id: number;
+  name: string;
+  avatar?: string;
+  device_id?: string;
+  status: 'online' | 'offline';
+  relationship?: string;
+  last_activity?: string;
+  health_data?: HealthData;
+}
+
+export interface HealthData {
+  heart_rate?: number;
+  steps?: number;
+  sleep_hours?: number;
+  last_updated?: string;
+}
+
+// Chat Types
+export interface Message {
+  id: string;
+  role: 'user' | 'assistant';
+  content: string;
+  timestamp: Date;
+}
+
+export interface ChatResponse {
+  ok: boolean;
+  response: {
+    Command: string;
+    body: string;
+    language: string;
+  };
+  status: string;
+}
+
+// API Types
+export interface ApiError {
+  message: string;
+  code?: string;
+  status?: number;
+}
+
+export interface ApiResponse<T> {
+  data?: T;
+  error?: ApiError;
+  ok: boolean;
+}