fix: backdrop-blur-md для кнопки Регистрация

frontend/src/components/Header.tsx

@@ -52,7 +52,7 @@ export default function Header() {
             <button onClick={() => setShowLogin(true)} className="rounded-lg bg-white/10 backdrop-blur-md px-3 py-1 text-sm text-white hover:bg-white/20 transition">
               Войти
             </button>
-            <button onClick={() => setShowRegister(true)} className="rounded-lg bg-green-600 px-3 py-1 text-sm text-white hover:bg-green-500 transition">
+            <button onClick={() => setShowRegister(true)} className="rounded-lg bg-green-600/70 backdrop-blur-md px-3 py-1 text-sm text-white hover:bg-green-500 transition">
               Регистрация
             </button>
           </div>