Back to Top Button 组件
响应式“Back to Top”按钮，具有 Material Design 美学、单色配色方案和深色模式支持。它在右下角显示为浮动作按钮 （FAB）。
HTML 代码
<div class="fixed bottom-4 right-4 z-50">
<button aria-label="Scroll to top" class="dark:bg-gray-700 dark:hover:bg-gray-600 dark:text-gray-200 dark:shadow-lg focus:outline-none dark:focus:ring-gray-500 rounded-full bg-gray-800 p-3 text-white shadow-md transition-all duration-300 ease-in-out hover:scale-105 hover:bg-gray-700 focus:ring-4 focus:ring-gray-300 active:scale-95 md:p-4 lg:p-5">
<svg class="h-6 w-6 md:h-7 md:w-7 lg:h-8 lg:w-8" 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="M5 10l7-7m0 0l7 7m-7-7v18"></path>
</svg>
</button>
</div>