added Layout and weather card

frontend/src/Layout/Layout.tsx

@@ -0,0 +1,17 @@
+import React from "react";
+import Header from "../components/Header";
+
+type LayoutProps = {
+  children: React.ReactNode;
+};
+
+const Layout: React.FC<LayoutProps> = ({ children }) => {
+  return (
+    <div className="flex flex-col min-h-screen bg-gradient-to-br from-blue-50 via-blue-100 to-blue-200 dark:from-gray-900 dark:via-gray-950 dark:to-gray-900">
+      <Header />
+      <main>{children}</main>
+    </div>
+  );
+};
+
+export default Layout;