diff --git a/frontend/README.md b/frontend/README.md
index e215bc4..c3a98de 100644
--- a/frontend/README.md
+++ b/frontend/README.md
@@ -1,36 +1,95 @@
-This is a [Next.js](https://nextjs.org) project bootstrapped with [`create-next-app`](https://nextjs.org/docs/app/api-reference/cli/create-next-app).
+# Frontend Implementation
 
-## Getting Started
+This document provides an overview of the frontend implementation for the "Application de Création de Groupes" project.
 
-First, run the development server:
+## Architecture
 
-```bash
-npm run dev
-# or
-yarn dev
-# or
-pnpm dev
-# or
-bun dev
-```
+The frontend is built with Next.js 15 using the App Router architecture. It follows a component-based approach with a clear separation of concerns:
 
-Open [http://localhost:3000](http://localhost:3000) with your browser to see the result.
+- **app/**: Contains all the pages and layouts organized by route
+- **components/**: Reusable UI components
+- **lib/**: Utility functions, hooks, and services
 
-You can start editing the page by modifying `app/page.tsx`. The page auto-updates as you edit the file.
+## Authentication Flow
 
-This project uses [`next/font`](https://nextjs.org/docs/app/building-your-application/optimizing/fonts) to automatically optimize and load [Geist](https://vercel.com/font), a new font family for Vercel.
+The application uses GitHub OAuth for authentication:
 
-## Learn More
+1. User clicks "Login with GitHub" on the login page
+2. User is redirected to GitHub for authorization
+3. GitHub redirects back to our callback page with an authorization code
+4. The callback page exchanges the code for an access token
+5. User information is stored in the AuthContext and localStorage
+6. User is redirected to the dashboard or the original page they were trying to access
 
-To learn more about Next.js, take a look at the following resources:
+### Authentication Components
 
-- [Next.js Documentation](https://nextjs.org/docs) - learn about Next.js features and API.
-- [Learn Next.js](https://nextjs.org/learn) - an interactive Next.js tutorial.
+- **AuthProvider**: Context provider that manages authentication state
+- **AuthLoading**: Component that displays a loading screen during authentication checks
+- **useAuth**: Hook to access authentication state and methods
 
-You can check out [the Next.js GitHub repository](https://github.com/vercel/next.js) - your feedback and contributions are welcome!
+## API Communication
 
-## Deploy on Vercel
+All API communication is centralized in the `lib/api.ts` file, which provides:
 
-The easiest way to deploy your Next.js app is to use the [Vercel Platform](https://vercel.com/new?utm_medium=default-template&filter=next.js&utm_source=create-next-app&utm_campaign=create-next-app-readme) from the creators of Next.js.
+- A base `fetchAPI` function with error handling and authentication
+- Specific API modules for different resources (auth, projects, persons, tags, groups)
+- Type-safe methods for all API operations
 
-Check out our [Next.js deployment documentation](https://nextjs.org/docs/app/building-your-application/deploying) for more details.
+## Protected Routes
+
+All authenticated routes are protected by:
+
+1. **Middleware**: Redirects unauthenticated users to the login page
+2. **AuthLoading**: Shows a loading screen during authentication checks
+3. **AuthContext**: Provides user information and authentication methods
+
+## Layout Structure
+
+The application uses a nested layout structure:
+
+- **RootLayout**: Provides global styles and the AuthProvider
+- **DashboardLayout**: Provides the sidebar navigation and user interface for authenticated pages
+- **AdminLayout**: Provides the admin interface for admin-only pages
+
+## Components
+
+### UI Components
+
+The application uses ShadcnUI for UI components, which provides:
+
+- A consistent design system
+- Accessible components
+- Dark mode support
+
+### Custom Components
+
+- **dashboard-layout.tsx**: Main layout for authenticated pages
+- **auth-loading.tsx**: Loading component for authentication checks
+- **admin-layout.tsx**: Layout for admin pages
+
+## Future Development
+
+### Adding New Pages
+
+1. Create a new directory in the `app/` folder
+2. Create a `page.tsx` file with your page content
+3. Create a `layout.tsx` file that uses the appropriate layout and AuthLoading component
+
+### Adding New API Endpoints
+
+1. Add new methods to the appropriate API module in `lib/api.ts`
+2. Use the methods in your components with the `useEffect` hook or event handlers
+
+### Adding New Features
+
+1. Create new components in the `components/` folder
+2. Use the components in your pages
+3. Add new API methods if needed
+
+## Best Practices
+
+- Use the AuthContext for authentication-related operations
+- Use the API service for all API communication
+- Wrap authenticated pages with the AuthLoading component
+- Use TypeScript for type safety
+- Follow the component-based architecture
\ No newline at end of file
diff --git a/frontend/docs/RESPONSIVE_DESIGN.md b/frontend/docs/RESPONSIVE_DESIGN.md
new file mode 100644
index 0000000..6cea565
--- /dev/null
+++ b/frontend/docs/RESPONSIVE_DESIGN.md
@@ -0,0 +1,91 @@
+# Responsive Design Patterns
+
+This document outlines the responsive design patterns used in the application to ensure a consistent user experience across different devices and screen sizes.
+
+## Breakpoints
+
+The application uses the following breakpoints, based on Tailwind CSS defaults:
+
+- **sm**: 640px and up (small devices like large phones and small tablets)
+- **md**: 768px and up (medium devices like tablets)
+- **lg**: 1024px and up (large devices like desktops)
+- **xl**: 1280px and up (extra large devices)
+- **2xl**: 1536px and up (very large screens)
+
+## Viewport Configuration
+
+The application uses the following viewport configuration in the root layout:
+
+```tsx
+export const viewport: Viewport = {
+  width: "device-width",
+  initialScale: 1,
+  maximumScale: 1,
+  userScalable: true,
+};
+```
+
+This ensures proper scaling on mobile devices while allowing users to zoom if needed.
+
+## Layout Patterns
+
+### Responsive Container
+
+- Use `container` class with responsive padding: `px-4 md:px-6`
+- Example: `<div className="container px-4 md:px-6">`
+
+### Responsive Flexbox
+
+- Stack elements vertically on small screens, horizontally on larger screens
+- Example: `<div className="flex flex-col sm:flex-row">`
+
+### Responsive Grid
+
+- Single column on small screens, multiple columns on larger screens
+- Example: `<div className="grid sm:grid-cols-2 lg:grid-cols-3">`
+
+### Responsive Spacing
+
+- Less padding on small screens, more on larger screens
+- Example: `<main className="p-4 sm:p-6">`
+
+## Component Patterns
+
+### Responsive Typography
+
+- Smaller font sizes on mobile, larger on desktop
+- Example: `<h1 className="text-2xl sm:text-3xl font-bold">`
+
+### Responsive Buttons
+
+- Full-width on small screens, auto-width on larger screens
+- Example: `<Button className="w-full sm:w-auto">`
+
+### Responsive Tables
+
+- Card layout on small screens, table layout on larger screens
+- Hide less important columns on small screens
+- Add horizontal scrolling for tables that don't fit
+- Example: See the projects page implementation
+
+### Responsive Forms
+
+- Stack form actions on small screens, side-by-side on larger screens
+- Adjust button order for mobile-first experience
+- Example: `<CardFooter className="flex flex-col sm:flex-row gap-2">`
+
+### Responsive Navigation
+
+- Use a sidebar that collapses to an icon or off-canvas menu on small screens
+- Use a dropdown or hamburger menu for mobile navigation
+- Example: See the `Sidebar` component implementation
+
+## Best Practices
+
+1. **Mobile-First Approach**: Start with the mobile layout and progressively enhance for larger screens
+2. **Consistent Patterns**: Use the same responsive patterns throughout the application
+3. **Avoid Fixed Widths**: Use relative units (%, rem) and flexible layouts
+4. **Test on Real Devices**: Verify the responsive design on actual devices, not just browser emulation
+5. **Consider Touch Targets**: Make interactive elements large enough for touch (at least 44x44px)
+6. **Optimize Images**: Use responsive images with appropriate sizes for different devices
+7. **Performance**: Ensure the application performs well on mobile devices with potentially slower connections
\ No newline at end of file
diff --git a/frontend/lib/api.ts b/frontend/lib/api.ts
new file mode 100644
index 0000000..071e8cb
--- /dev/null
+++ b/frontend/lib/api.ts
@@ -0,0 +1,301 @@
+/**
+ * API Service
+ * 
+ * This service centralizes all API communication with the backend.
+ * It provides methods for authentication, projects, persons, and tags.
+ */
+
+const API_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:3000';
+
+/**
+ * Base fetch function with error handling and authentication
+ */
+async function fetchAPI(endpoint: string, options: RequestInit = {}) {
+  // Set default headers
+  const headers: Record<string, string> = {
+    'Content-Type': 'application/json',
+    ...(options.headers as Record<string, string> || {}),
+  };
+
+  // Get token from localStorage if available (client-side only)
+  if (typeof window !== 'undefined') {
+    const token = localStorage.getItem('auth_token');
+    if (token) {
+      headers['Authorization'] = `Bearer ${token}`;
+    }
+  }
+
+  // Prepare fetch options
+  const fetchOptions: RequestInit = {
+    ...options,
+    headers,
+    credentials: 'include', // Include cookies for session management
+  };
+
+  try {
+    const response = await fetch(`${API_URL}${endpoint}`, fetchOptions);
+
+    // Handle HTTP errors
+    if (!response.ok) {
+      const errorData = await response.json().catch(() => ({}));
+      throw new Error(errorData.message || `API error: ${response.status}`);
+    }
+
+    // Parse JSON response if content exists
+    const contentType = response.headers.get('content-type');
+    if (contentType && contentType.includes('application/json')) {
+      return await response.json();
+    }
+
+    return response;
+  } catch (error) {
+    console.error('API request failed:', error);
+    throw error;
+  }
+}
+
+/**
+ * Authentication API
+ */
+export const authAPI = {
+  /**
+   * Get GitHub OAuth URL
+   */
+  getGitHubOAuthUrl: async () => {
+    return fetchAPI('/auth/github', { method: 'GET' });
+  },
+
+  /**
+   * Exchange code for access token
+   */
+  githubCallback: async (code: string) => {
+    return fetchAPI('/auth/github/callback', {
+      method: 'POST',
+      body: JSON.stringify({ code }),
+    });
+  },
+
+  /**
+   * Logout user
+   */
+  logout: async () => {
+    return fetchAPI('/auth/logout', { method: 'POST' });
+  },
+
+  /**
+   * Get current user
+   */
+  getCurrentUser: async () => {
+    return fetchAPI('/auth/me', { method: 'GET' });
+  },
+};
+
+/**
+ * Projects API
+ */
+export const projectsAPI = {
+  /**
+   * Get all projects
+   */
+  getProjects: async () => {
+    return fetchAPI('/projects', { method: 'GET' });
+  },
+
+  /**
+   * Get project by ID
+   */
+  getProject: async (id: string) => {
+    return fetchAPI(`/projects/${id}`, { method: 'GET' });
+  },
+
+  /**
+   * Create new project
+   */
+  createProject: async (data: any) => {
+    return fetchAPI('/projects', {
+      method: 'POST',
+      body: JSON.stringify(data),
+    });
+  },
+
+  /**
+   * Update project
+   */
+  updateProject: async (id: string, data: any) => {
+    return fetchAPI(`/projects/${id}`, {
+      method: 'PATCH',
+      body: JSON.stringify(data),
+    });
+  },
+
+  /**
+   * Delete project
+   */
+  deleteProject: async (id: string) => {
+    return fetchAPI(`/projects/${id}`, { method: 'DELETE' });
+  },
+};
+
+/**
+ * Persons API
+ */
+export const personsAPI = {
+  /**
+   * Get all persons for a project
+   */
+  getPersons: async (projectId: string) => {
+    return fetchAPI(`/projects/${projectId}/persons`, { method: 'GET' });
+  },
+
+  /**
+   * Get person by ID
+   */
+  getPerson: async (id: string) => {
+    return fetchAPI(`/persons/${id}`, { method: 'GET' });
+  },
+
+  /**
+   * Create new person
+   */
+  createPerson: async (projectId: string, data: any) => {
+    return fetchAPI(`/projects/${projectId}/persons`, {
+      method: 'POST',
+      body: JSON.stringify(data),
+    });
+  },
+
+  /**
+   * Update person
+   */
+  updatePerson: async (id: string, data: any) => {
+    return fetchAPI(`/persons/${id}`, {
+      method: 'PATCH',
+      body: JSON.stringify(data),
+    });
+  },
+
+  /**
+   * Delete person
+   */
+  deletePerson: async (id: string) => {
+    return fetchAPI(`/persons/${id}`, { method: 'DELETE' });
+  },
+};
+
+/**
+ * Tags API
+ */
+export const tagsAPI = {
+  /**
+   * Get all tags
+   */
+  getTags: async () => {
+    return fetchAPI('/tags', { method: 'GET' });
+  },
+
+  /**
+   * Get tag by ID
+   */
+  getTag: async (id: string) => {
+    return fetchAPI(`/tags/${id}`, { method: 'GET' });
+  },
+
+  /**
+   * Create new tag
+   */
+  createTag: async (data: any) => {
+    return fetchAPI('/tags', {
+      method: 'POST',
+      body: JSON.stringify(data),
+    });
+  },
+
+  /**
+   * Update tag
+   */
+  updateTag: async (id: string, data: any) => {
+    return fetchAPI(`/tags/${id}`, {
+      method: 'PATCH',
+      body: JSON.stringify(data),
+    });
+  },
+
+  /**
+   * Delete tag
+   */
+  deleteTag: async (id: string) => {
+    return fetchAPI(`/tags/${id}`, { method: 'DELETE' });
+  },
+};
+
+/**
+ * Groups API
+ */
+export const groupsAPI = {
+  /**
+   * Get all groups for a project
+   */
+  getGroups: async (projectId: string) => {
+    return fetchAPI(`/projects/${projectId}/groups`, { method: 'GET' });
+  },
+
+  /**
+   * Get group by ID
+   */
+  getGroup: async (id: string) => {
+    return fetchAPI(`/groups/${id}`, { method: 'GET' });
+  },
+
+  /**
+   * Create new group
+   */
+  createGroup: async (projectId: string, data: any) => {
+    return fetchAPI(`/projects/${projectId}/groups`, {
+      method: 'POST',
+      body: JSON.stringify(data),
+    });
+  },
+
+  /**
+   * Update group
+   */
+  updateGroup: async (id: string, data: any) => {
+    return fetchAPI(`/groups/${id}`, {
+      method: 'PATCH',
+      body: JSON.stringify(data),
+    });
+  },
+
+  /**
+   * Delete group
+   */
+  deleteGroup: async (id: string) => {
+    return fetchAPI(`/groups/${id}`, { method: 'DELETE' });
+  },
+
+  /**
+   * Add person to group
+   */
+  addPersonToGroup: async (groupId: string, personId: string) => {
+    return fetchAPI(`/groups/${groupId}/persons/${personId}`, {
+      method: 'POST',
+    });
+  },
+
+  /**
+   * Remove person from group
+   */
+  removePersonFromGroup: async (groupId: string, personId: string) => {
+    return fetchAPI(`/groups/${groupId}/persons/${personId}`, {
+      method: 'DELETE',
+    });
+  },
+};
+
+export default {
+  auth: authAPI,
+  projects: projectsAPI,
+  persons: personsAPI,
+  tags: tagsAPI,
+  groups: groupsAPI,
+};
diff --git a/frontend/lib/auth-context.tsx b/frontend/lib/auth-context.tsx
new file mode 100644
index 0000000..d87228a
--- /dev/null
+++ b/frontend/lib/auth-context.tsx
@@ -0,0 +1,145 @@
+"use client";
+
+import { createContext, useContext, useEffect, useState, ReactNode } from "react";
+import { useRouter } from "next/navigation";
+import api from "./api";
+
+// Define the User type
+interface User {
+  id: string;
+  name: string;
+  avatar?: string;
+  role: string;
+}
+
+// Define the AuthContext type
+interface AuthContextType {
+  user: User | null;
+  isLoading: boolean;
+  isAuthenticated: boolean;
+  login: (code: string) => Promise<void>;
+  logout: () => Promise<void>;
+  checkAuth: () => Promise<boolean>;
+}
+
+// Create the AuthContext
+const AuthContext = createContext<AuthContextType | undefined>(undefined);
+
+// Create a provider component
+export function AuthProvider({ children }: { children: ReactNode }) {
+  const [user, setUser] = useState<User | null>(null);
+  const [isLoading, setIsLoading] = useState<boolean>(true);
+  const router = useRouter();
+
+  // Check if the user is authenticated on mount
+  useEffect(() => {
+    const initAuth = async () => {
+      setIsLoading(true);
+      try {
+        await checkAuth();
+      } catch (error) {
+        console.error("Auth initialization error:", error);
+      } finally {
+        setIsLoading(false);
+      }
+    };
+
+    initAuth();
+  }, []);
+
+  // Check if the user is authenticated
+  const checkAuth = async (): Promise<boolean> => {
+    try {
+      // Try to get the current user from the API
+      const userData = await api.auth.getCurrentUser();
+      
+      if (userData) {
+        setUser(userData);
+        
+        // Update localStorage with user data
+        localStorage.setItem('user_role', userData.role);
+        localStorage.setItem('user_name', userData.name);
+        if (userData.avatar) {
+          localStorage.setItem('user_avatar', userData.avatar);
+        }
+        
+        return true;
+      }
+      
+      return false;
+    } catch (error) {
+      console.error("Auth check error:", error);
+      setUser(null);
+      return false;
+    }
+  };
+
+  // Login function
+  const login = async (code: string): Promise<void> => {
+    setIsLoading(true);
+    try {
+      const data = await api.auth.githubCallback(code);
+      
+      if (data.user) {
+        setUser(data.user);
+        
+        // Store user info in localStorage
+        localStorage.setItem('auth_token', data.accessToken);
+        localStorage.setItem('user_role', data.user.role);
+        localStorage.setItem('user_name', data.user.name);
+        if (data.user.avatar) {
+          localStorage.setItem('user_avatar', data.user.avatar);
+        }
+      }
+    } catch (error) {
+      console.error("Login error:", error);
+      throw error;
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  // Logout function
+  const logout = async (): Promise<void> => {
+    setIsLoading(true);
+    try {
+      await api.auth.logout();
+      
+      // Clear user state and localStorage
+      setUser(null);
+      localStorage.removeItem('auth_token');
+      localStorage.removeItem('user_role');
+      localStorage.removeItem('user_name');
+      localStorage.removeItem('user_avatar');
+      
+      // Redirect to login page
+      router.push('/auth/login');
+    } catch (error) {
+      console.error("Logout error:", error);
+      throw error;
+    } finally {
+      setIsLoading(false);
+    }
+  };
+
+  // Create the context value
+  const value = {
+    user,
+    isLoading,
+    isAuthenticated: !!user,
+    login,
+    logout,
+    checkAuth,
+  };
+
+  return <AuthContext.Provider value={value}>{children}</AuthContext.Provider>;
+}
+
+// Create a hook to use the AuthContext
+export function useAuth() {
+  const context = useContext(AuthContext);
+  if (context === undefined) {
+    throw new Error("useAuth must be used within an AuthProvider");
+  }
+  return context;
+}
\ No newline at end of file
diff --git a/frontend/middleware.ts b/frontend/middleware.ts
new file mode 100644
index 0000000..f5e7390
--- /dev/null
+++ b/frontend/middleware.ts
@@ -0,0 +1,60 @@
+import { NextResponse } from 'next/server';
+import type { NextRequest } from 'next/server';
+
+// Define public routes that don't require authentication
+const publicRoutes = [
+  '/',
+  '/auth/login',
+  '/auth/callback',
+];
+
+// Define routes that require admin role
+const adminRoutes = [
+  '/admin',
+];
+
+export function middleware(request: NextRequest) {
+  const { pathname } = request.nextUrl;
+
+  // Allow access to public routes without authentication
+  if (publicRoutes.some(route => pathname === route || pathname.startsWith(`${route}/`))) {
+    return NextResponse.next();
+  }
+
+  // Get the auth token from cookies
+  const token = request.cookies.get('auth_token')?.value;
+  const userRole = request.cookies.get('user_role')?.value;
+
+  // If no token, redirect to login
+  if (!token) {
+    // Store the original URL to redirect back after login
+    const url = new URL('/auth/login', request.url);
+    url.searchParams.set('callbackUrl', pathname);
+    return NextResponse.redirect(url);
+  }
+
+  // Check if the route requires admin role
+  if (adminRoutes.some(route => pathname === route || pathname.startsWith(`${route}/`))) {
+    // If not admin role, redirect to dashboard
+    if (userRole !== 'ADMIN') {
+      return NextResponse.redirect(new URL('/dashboard', request.url));
+    }
+  }
+
+  return NextResponse.next();
+}
+
+// Configure the middleware to run on all routes except static files and api routes
+export const config = {
+  matcher: [
+    /*
+     * Match all request paths except for:
+     * 1. /api routes
+     * 2. /_next (Next.js internals)
+     * 3. /_static (static files)
+     * 4. /_vercel (Vercel internals)
+     * 5. /favicon.ico, /robots.txt, /sitemap.xml (common static files)
+     */
+    '/((?!api|_next|_static|_vercel|favicon.ico|robots.txt|sitemap.xml).*)',
+  ],
+};
diff --git a/frontend/package.json b/frontend/package.json
index e1dfa58..8443875 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -52,6 +52,7 @@
     "react-resizable-panels": "^3.0.2",
     "recharts": "^2.15.3",
     "sonner": "^2.0.3",
+    "swr": "^2.3.3",
     "tailwind-merge": "^3.3.0",
     "vaul": "^1.1.2",
     "zod": "^3.24.4"