RetroHeaderComponent (レトロヘッダーコンポーネント)

<header class="bg-gray-200 dark:bg-gray-800 text-gray-800 dark:text-white p-4">
  <div class="container mx-auto flex justify-between items-center">
    <div class="text-2xl font-bold">RetroHeader</div>
    <nav class="hidden md:flex space-x-4">
      <a href="#" class="hover:underline">Home</a>
      <a href="#" class="hover:underline">About</a>
      <a href="#" class="hover:underline">Contact</a>
    </nav>
    <div class="md:hidden">
      <button class="text-gray-800 dark:text-white focus:outline-none">
        <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg"><path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M4 6h16M4 12h16M4 18h16"></path></svg>
      </button>
    </div>
  </div>
</header>