feat: implement responsive Navbar component and integrate into App

frontend/src/App.tsx

@@ -8,13 +8,18 @@ import SignIn from "./pages/Signin";
 import Browse from "./pages/Browse";
 import Sell from "./pages/Sell";
 import ProductDetailsPage from "./pages/ProductDetail";
+import Navbar from "./components/Navbar";
 const queryClient = new QueryClient();
 
 const App = () => (
   <QueryClientProvider client={queryClient}>
     <TooltipProvider>
       <Toaster />
+
       <BrowserRouter>
+            <Navbar />
+      <div className="pt-[50px]">
+
         <Routes>
           <Route path="/" element={<Index />} />
           <Route path="/signup" element={<SignUp />} />
@@ -23,6 +28,7 @@ const App = () => (
           <Route path="/product/:id" element={<ProductDetailsPage />} />
           <Route path="/sell" element={<Sell />} />
         </Routes>
+        </div>
       </BrowserRouter>
     </TooltipProvider>
   </QueryClientProvider>

frontend/src/components/Navbar.tsx

@@ -0,0 +1,110 @@
+import React, { useState } from "react";
+import { Link, useNavigate, useLocation } from "react-router-dom";
+import { Button } from "@/components/ui/button";
+import { Menu, X } from "lucide-react";
+
+const Navbar: React.FC = () => {
+  const [isOpen, setIsOpen] = useState(false);
+  const navigate = useNavigate();
+  const location = useLocation();
+
+  const handleNavClick = (path: string) => {
+    navigate(path);
+    setIsOpen(false);
+  };
+
+  const navLinks = [
+    { name: "Home", path: "/" },
+    { name: "Browse", path: "/browse" },
+    { name: "Sell", path: "/sell" },
+  ];
+
+  return (
+    <nav className="w-full bg-white/80 backdrop-blur-md shadow-sm fixed top-0 left-0 z-50">
+      <div className="container mx-auto px-6 py-3 flex items-center justify-between">
+        <Link
+          to="/"
+          className="text-2xl font-extrabold text-blue-800 tracking-tight hover:opacity-80 transition"
+        >
+          UniLoot
+        </Link>
+
+        <div className="hidden md:flex items-center gap-8">
+          {navLinks.map((link) => (
+            <button
+              key={link.name}
+              onClick={() => handleNavClick(link.path)}
+              className={`text-base font-semibold transition-colors duration-300 ${
+                location.pathname === link.path
+                  ? "text-blue-800"
+                  : "text-gray-700 hover:text-blue-800"
+              }`}
+            >
+              {link.name}
+            </button>
+          ))}
+        </div>
+
+        <div className="hidden md:flex items-center gap-3">
+          <Button
+            variant="outline"
+            className="border-2 border-blue-800 text-blue-800 hover:bg-blue-800 hover:text-white transition"
+            onClick={() => handleNavClick("/signin")}
+          >
+            Sign In
+          </Button>
+          <Button
+            className="bg-blue-800 text-white hover:bg-blue-900 transition"
+            onClick={() => handleNavClick("/signup")}
+          >
+            Sign Up
+          </Button>
+        </div>
+
+        <button
+          onClick={() => setIsOpen(!isOpen)}
+          className="md:hidden text-blue-800 focus:outline-none"
+        >
+          {isOpen ? <X size={28} /> : <Menu size={28} />}
+        </button>
+      </div>
+
+      {isOpen && (
+        <div className="md:hidden bg-white border-t border-gray-200 shadow-md">
+          <div className="flex flex-col items-center py-4 space-y-4">
+            {navLinks.map((link) => (
+              <button
+                key={link.name}
+                onClick={() => handleNavClick(link.path)}
+                className={`text-lg font-semibold ${
+                  location.pathname === link.path
+                    ? "text-blue-800"
+                    : "text-gray-700 hover:text-blue-800"
+                }`}
+              >
+                {link.name}
+              </button>
+            ))}
+            <div className="flex flex-col gap-2 pt-3 w-4/5">
+              <Button
+                variant="outline"
+                className="border-2 border-blue-800 text-blue-800 hover:bg-blue-800 hover:text-white w-full"
+                onClick={() => handleNavClick("/signin")}
+              >
+                Sign In
+              </Button>
+              <Button
+                className="bg-blue-800 text-white hover:bg-blue-900 w-full"
+                onClick={() => handleNavClick("/signup")}
+              >
+                Sign Up
+              </Button>
+            </div>
+          </div>
+        </div>
+      )}
+    </nav>
+  );
+};
+
+export default Navbar;