## Description Add a simple 404 Not Found page for users who navigate to an invalid or non-existent route. The page should follow the application's existing design. ## Acceptance criteria - [x] Display a 404 page for unknown routes. - [x] Provide a clear message indicating that the page was not found. - [x] Include a button or link to return to the home page. - [x] Ensure the page is responsive and consistent with the existing design. ## Dependencies None