标头组件

<header class="bg-white dark:bg-gray-900 p-4 shadow-md">
  <div class="container mx-auto flex justify-between items-center">
    <!-- Logo or Site Title -->
    <a href="#" class="text-2xl font-bold text-gray-900 dark:text-white">SocialSite</a>

    <!-- Search Bar -->
    <div class="flex-grow mx-4 max-w-xl">
      <input type="text" placeholder="Search..." class="w-full p-2 rounded-lg bg-gray-200 dark:bg-gray-700 text-gray-900 dark:text-white placeholder-gray-500 dark:placeholder-gray-400 focus:outline-none focus:ring-2 focus:ring-gray-300 dark:focus:ring-gray-600">
    </div>

    <!-- User Avatar/Menu -->
    <div class="flex items-center space-x-4">
      <img src="https://randomuser.me/api/portraits/men/32.jpg" alt="User Avatar" class="w-10 h-10 rounded-full border-2 border-gray-300 dark:border-gray-600">
    </div>
  </div>
</header>