final touches

frontend/src/main.jsx

@@ -42,7 +42,9 @@ function Header() {
       <div className="container">
         <nav className="nav">
           <div className="nav-brand">
-            <h2>WTP</h2>
+            <Link to="/challenges" style={{ textDecoration: 'none', color: 'inherit' }}>
+              <h2>WTP</h2>
+            </Link>
             <button 
               className={`hamburger ${mobileMenuOpen ? 'active' : ''}`}
               onClick={() => setMobileMenuOpen(!mobileMenuOpen)}