added tailwind design classes, and installed tailwindcss properly.

frontend/src/Layout/Layout.tsx

@@ -8,10 +8,15 @@ type LayoutProps = {
 
 const Layout: React.FC<LayoutProps> = ({ children }) => {
   return (
-    <div>
+    <div className="min-h-screen bg-gradient-to-br from-blue-100 to-blue-300 flex flex-col">
       <Header />
-      <ToastContainer />
-      <main>{children}</main>
+      <ToastContainer
+        position="top-right"
+        autoClose={3000}
+        hideProgressBar
+        theme="colored"
+      />
+      <main className="flex-1 container mx-auto px-4 py-8">{children}</main>
     </div>
   );
 };