diff --git a/components/Layout.tsx b/components/Layout.tsx
index c2d3949..833ceff 100644
--- a/components/Layout.tsx
+++ b/components/Layout.tsx
@@ -1,7 +1,7 @@
 import React, { useState, useEffect } from 'react';
 import { NavLink, useLocation, useNavigate } from 'react-router-dom';
 import { LayoutDashboard, Users, UserCircle, Bell, Search, Menu, X, LogOut, Hexagon, Settings, Building2 } from 'lucide-react';
-import { USERS } from '../constants';
+import { getAttendances, getUsers, getUserById } from '../services/dataService';
 import { User } from '../types';
 
 const SidebarItem = ({ to, icon: Icon, label, collapsed }: { to: string, icon: any, label: string, collapsed: boolean }) => (
@@ -24,20 +24,33 @@ export const Layout: React.FC<{ children: React.ReactNode }> = ({ children }) =>
   const [isMobileMenuOpen, setIsMobileMenuOpen] = useState(false);
   const location = useLocation();
   const navigate = useNavigate();
-  const [currentUser, setCurrentUser] = useState<User>(USERS[1]); // Default to standard user fallback
+  const [currentUser, setCurrentUser] = useState<User | null>(null);
 
   useEffect(() => {
-    const storedUserId = localStorage.getItem('ctms_user_id');
-    if (storedUserId) {
-      const user = USERS.find(u => u.id === storedUserId);
-      if (user) {
-        setCurrentUser(user);
+    const fetchCurrentUser = async () => {
+      const storedUserId = localStorage.getItem('ctms_user_id');
+      if (!storedUserId) {
+        navigate('/login');
+        return;
       }
-    }
-  }, []);
+
+      try {
+        const user = await getUserById(storedUserId);
+        if (user) {
+          setCurrentUser(user);
+        } else {
+          navigate('/login');
+        }
+      } catch (err) {
+        console.error("Layout fetch failed:", err);
+      }
+    };
+    fetchCurrentUser();
+  }, [navigate]);
 
   const handleLogout = () => {
     localStorage.removeItem('ctms_user_id');
+    localStorage.removeItem('ctms_tenant_id');
     navigate('/login');
   };
 
@@ -52,6 +65,8 @@ export const Layout: React.FC<{ children: React.ReactNode }> = ({ children }) =>
     return 'CTMS';
   };
 
+  if (!currentUser) return null;
+
   const isSuperAdmin = currentUser.role === 'super_admin';
 
   return (
diff --git a/pages/Login.tsx b/pages/Login.tsx
index 3884325..c4d8ab2 100644
--- a/pages/Login.tsx
+++ b/pages/Login.tsx
@@ -1,7 +1,7 @@
 import React, { useState } from 'react';
 import { useNavigate } from 'react-router-dom';
 import { Hexagon, Lock, Mail, ArrowRight, Loader2, Info } from 'lucide-react';
-import { USERS } from '../constants';
+import { getUsers } from '../services/dataService';
 
 export const Login: React.FC = () => {
   const navigate = useNavigate();
@@ -10,22 +10,22 @@ export const Login: React.FC = () => {
   const [password, setPassword] = useState('password');
   const [error, setError] = useState('');
 
-  const handleLogin = (e: React.FormEvent) => {
+  const handleLogin = async (e: React.FormEvent) => {
     e.preventDefault();
     setIsLoading(true);
     setError('');
     
-    // Simulate API call and validation
-    setTimeout(() => {
-      const user = USERS.find(u => u.email.toLowerCase() === email.toLowerCase());
+    try {
+      // Fetch all users to find match (simplified auth for demo)
+      const users = await getUsers('all');
+      const user = users.find(u => u.email.toLowerCase() === email.toLowerCase());
 
       if (user) {
-        // Mock Login: Save to local storage
         localStorage.setItem('ctms_user_id', user.id);
+        localStorage.setItem('ctms_tenant_id', user.tenant_id || '');
         
         setIsLoading(false);
         
-        // Redirect based on role
         if (user.role === 'super_admin') {
           navigate('/super-admin');
         } else {
@@ -33,9 +33,13 @@ export const Login: React.FC = () => {
         }
       } else {
         setIsLoading(false);
-        setError('Usuário não encontrado. Tente lidya@fasto.com ou root@system.com');
+        setError('Usuário não encontrado.');
       }
-    }, 1000);
+    } catch (err) {
+      console.error("Login error:", err);
+      setIsLoading(false);
+      setError('Erro ao conectar ao servidor.');
+    }
   };
 
   const fillCredentials = (type: 'admin' | 'super') => {
diff --git a/pages/UserProfile.tsx b/pages/UserProfile.tsx
index 8fc90a6..ae073ff 100644
--- a/pages/UserProfile.tsx
+++ b/pages/UserProfile.tsx
@@ -1,24 +1,33 @@
 import React, { useState, useEffect } from 'react';
 import { Camera, Save, Mail, User as UserIcon, Building, Shield, Loader2, CheckCircle2 } from 'lucide-react';
-import { USERS } from '../constants';
+import { getUserById } from '../services/dataService';
 import { User } from '../types';
 
 export const UserProfile: React.FC = () => {
-  // Simulating logged-in user state
   const [user, setUser] = useState<User | null>(null);
   const [isLoading, setIsLoading] = useState(false);
   const [isSuccess, setIsSuccess] = useState(false);
   
-  // Form State
   const [name, setName] = useState('');
   const [bio, setBio] = useState('');
   
   useEffect(() => {
-    // Simulate fetching user data
-    const currentUser = USERS[0];
-    setUser(currentUser);
-    setName(currentUser.name);
-    setBio(currentUser.bio || '');
+    const fetchUser = async () => {
+      const storedId = localStorage.getItem('ctms_user_id');
+      if (storedId) {
+        try {
+          const fetchedUser = await getUserById(storedId);
+          if (fetchedUser) {
+            setUser(fetchedUser);
+            setName(fetchedUser.name);
+            setBio(fetchedUser.bio || '');
+          }
+        } catch (err) {
+          console.error("Error fetching profile:", err);
+        }
+      }
+    };
+    fetchUser();
   }, []);
 
   const handleSubmit = (e: React.FormEvent) => {