Кнопка «Наверх»

                <div class="fixed bottom-4 right-4">
  <a href="#" class="bg-blue-500 text-white p-3 rounded-full shadow-md transition-opacity duration-300 opacity-0 group-hover:opacity-100 dark:bg-blue-700 dark:text-gray-200">
    <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="M5 10l7-7m0 0l7 7m-7-7v18"></path></svg>
  </a>
</div>

<style>
  /* This simple example uses CSS for smooth scrolling. For a production site, you might use a small amount of JavaScript for better compatibility and control over the scroll behavior and when the button appears. */
  html {
    scroll-behavior: smooth;
  }

  /* Basic example to show/hide the button based on scroll position. 
     A robust solution would involve JavaScript Intersection Observer or scroll events. */
  body:before {
    content: "";
    height: 200vh; /* Simulate a long page */
    display: block;
  }

  .group-hover\:opacity-100:hover + .fixed a {
      opacity: 1; /* This part is flawed for demonstrating scroll-based visibility without JS */
  }

  /* A better approach for scroll-based visibility would require JavaScript */
  .fixed a {
      /* Initially hidden, JS would make it visible on scroll */
      opacity: 0;
      transition: opacity 0.3s ease-in-out;
  }


</style>
              

                <a href="#" class="fixed bottom-6 right-6 bg-blue-500 hover:bg-blue-700 text-white p-3 rounded-full shadow-lg transition-colors duration-300 dark:bg-blue-700 dark:hover:bg-blue-900">
  <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="M5 10l7-7m0 0l7 7m-7-7v18"></path>
  </svg>
</a>
              

                <div class="fixed bottom-8 right-8">
    <a href="#" class="flex items-center justify-center w-12 h-12 rounded-full bg-gray-600 text-white shadow-lg transition-all ease-in-out duration-300 hover:bg-gray-500 dark:bg-gray-800 dark:hover:bg-gray-700">
        <svg xmlns="http://www.w3.org/2000/svg" class="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor">
            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 4v16m8-8H4" />
        </svg>
    </a>
</div>
              

                <div class="fixed bottom-5 right-5 z-50">
    <a href="#top" class="flex items-center justify-center w-12 h-12 rounded-full bg-gray-800 text-white hover:bg-gray-600 dark:bg-gray-900 dark:text-gray-300 dark:hover:bg-gray-700 transition-all duration-300 shadow-lg">
        ⬆️
    </a>
</div>

<div class="h-screen bg-gray-100 dark:bg-gray-800" id="top">
    <div class="container mx-auto p-5">
        <h1 class="text-3xl font-bold text-gray-900 dark:text-white">Portfolio</h1>
        <p class="text-gray-700 dark:text-gray-300">Showcasing my work and products.</p>
        <div class="grid grid-cols-1 md:grid-cols-2 lg:grid-cols-3 gap-5 mt-5">
            <div class="bg-white dark:bg-gray-700 p-5 shadow rounded-lg">
                <img src="https://picsum.photos/200" alt="Portfolio item" class="w-full rounded-lg">
                <h2 class="text-xl font-semibold text-gray-900 dark:text-white mt-2">Project Title</h2>
                <p class="text-gray-600 dark:text-gray-300">Description of the project goes here.</p>
            </div>
            <div class="bg-white dark:bg-gray-700 p-5 shadow rounded-lg">
                <img src="https://picsum.photos/201" alt="Portfolio item" class="w-full rounded-lg">
                <h2 class="text-xl font-semibold text-gray-900 dark:text-white mt-2">Project Title</h2>
                <p class="text-gray-600 dark:text-gray-300">Description of the project goes here.</p>
            </div>
            <div class="bg-white dark:bg-gray-700 p-5 shadow rounded-lg">
                <img src="https://picsum.photos/202" alt="Portfolio item" class="w-full rounded-lg">
                <h2 class="text-xl font-semibold text-gray-900 dark:text-white mt-2">Project Title</h2>
                <p class="text-gray-600 dark:text-gray-300">Description of the project goes here.</p>
            </div>
        </div>
    </div>
</div>
              

                <a href="#" class="fixed bottom-4 right-4 bg-red-500 dark:bg-cyan-500 text-yellow-300 dark:text-magenta-500 p-4 rounded-full shadow-lg transform transition-transform duration-300 hover:scale-110 focus:outline-none focus:ring-4 focus:ring-red-500 dark:focus:ring-cyan-500 border-4 border-black dark:border-white z-50">
    <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="M5 10l7-7m0 0l7 7m-7-7v18"></path>
    </svg>
</a>
              

                <button class="fixed bottom-5 right-5 bg-pink-300 text-white p-3 rounded-full shadow-lg transition-opacity hover:opacity-75 focus:outline-none dark:bg-pink-700 dark:text-gray-200">
  <svg xmlns="http://www.w3.org/2000/svg" class="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor">
    <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M5 10l7-7m0 0l7 7m-7-7v18" />
  </svg>
</button>
              

                <div class="fixed bottom-5 right-5">
    <a href="#" class="bg-white bg-opacity-30 backdrop-blur-md border border-gray-200 dark:bg-gray-800 dark:bg-opacity-30 dark:border-gray-600 text-gray-800 dark:text-gray-200 rounded-full p-3 shadow-lg hover:shadow-2xl transition-transform transform hover:scale-110">
        <svg xmlns="http://www.w3.org/2000/svg" class="h-6 w-6" fill="none" viewBox="0 0 24 24" stroke="currentColor">
            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 4v16m8-8H4" />
        </svg>
    </a>
</div>
              

                <button class="fixed bottom-4 right-4 bg-black text-white border-2 border-black group dark:bg-white dark:text-black dark:border-white">
  <span class="block px-6 py-3 text-xl font-bold group-hover:-translate-x-2 group-hover:-translate-y-2 transition-all">
    ⬆️
  </span>
</button>
              

                <div class="fixed bottom-5 right-5 z-50">
  <button
    class="back-to-top-btn bg-gradient-to-r from-pink-500 via-red-500 to-yellow-500 text-white p-4 rounded-full shadow-lg transform transition-transform duration-300 hover:scale-110 active:scale-95 focus:outline-none focus:ring-4 focus:ring-pink-300 dark:focus:ring-pink-800"
    aria-label="Back to top"
  >
    <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="M5 10l7-7m0 0l7 7m-7-7v18"
      ></path>
    </svg>
  </button>
</div>

<style>
  .back-to-top-btn {
    /* Adding basic 3D effect with box-shadow */
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2),
                0 6px 6px rgba(0, 0, 0, 0.2);
    transition: all 0.2s ease-in-out;
  }

  .back-to-top-btn:hover {
      box-shadow: 0 14px 28px rgba(0, 0, 0, 0.25),
                  0 10px 10px rgba(0, 0, 0, 0.22);
  }

  .back-to-top-btn:active {
      box-shadow: 0 1px 3px rgba(0, 0, 0, 0.12),
                  0 1px 2px rgba(0, 0, 0, 0.24);
  }
</style>
              

                <div class="fixed bottom-4 right-4 group">
  <button class="bg-blue-600 text-white px-4 py-2 rounded-lg shadow-lg 
                 transform transition-transform duration-300 
                 group-hover:scale-110 group-active:scale-90 
                 dark:bg-blue-800 dark:shadow-xl dark:group-hover:scale-110 dark:group-active:scale-90 
                 focus:outline-none focus:ring-2 focus:ring-blue-500 focus:ring-opacity-50">
    <svg class="h-6 w-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="M5 10l7-7m0 0l7 7m-7-7v18"></path>
    </svg>
  </button>
</div>