Animated Clouds in CSS

<div class="header">
  <h1>☁️ Animated Clouds</h1>
  <p>Pure CSS cloud animations with beautiful sky effects</p>
</div>

<div class="sky">
  <!-- Sun -->
  <div class="sun"></div>

  <!-- White Clouds -->
  <div class="cloud cloud-1"></div>
  <div class="cloud cloud-2"></div>
  <div class="cloud cloud-3"></div>
  <div class="cloud cloud-4"></div>
  <div class="cloud cloud-5"></div>
  <div class="cloud cloud-6"></div>
  <div class="cloud cloud-7"></div>
  <div class="cloud cloud-8"></div>

  <!-- Colored Background Clouds -->
  <div class="colored-cloud colored-cloud-1"></div>
  <div class="colored-cloud colored-cloud-2"></div>
  <div class="colored-cloud colored-cloud-3"></div>

  <!-- Flying Birds -->
  <div class="bird bird-1"></div>
  <div class="bird bird-2"></div>
  <div class="bird bird-3"></div>
</div>

<div class="info-section">
  <div class="info-card">
    <div class="info-icon">☁️</div>
    <div class="info-title">Realistic Clouds</div>
    <div class="info-desc">
      Multiple layers of animated clouds floating across the sky with varying speeds and sizes for realistic motion.
    </div>
  </div>

  <div class="info-card">
    <div class="info-icon">🎨</div>
    <div class="info-title">Pure CSS</div>
    <div class="info-desc">
      Created entirely with CSS animations - no JavaScript required. Smooth, performant, and lightweight animations.
    </div>
  </div>

  <div class="info-card">
    <div class="info-icon">✨</div>
    <div class="info-title">Beautiful Effects</div>
    <div class="info-desc">
      Includes glowing sun, flying birds, colored atmospheric clouds, and a dynamic gradient sky background.
    </div>
  </div>
</div>

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      background: linear-gradient(to bottom, #90e0ef 0%, #caf0f8 50%, #ade8f4 100%);
      min-height: 100vh;
      overflow-x: hidden;
      position: relative;
    }

    .header {
      text-align: center;
      color: white;
      padding: 40px 20px;
      position: relative;
      z-index: 10;
      text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
    }

    .header h1 {
      font-size: 3rem;
      font-weight: 700;
      margin-bottom: 10px;
      animation: fadeInDown 1s ease;
    }

    .header p {
      font-size: 1.2rem;
      opacity: 0.95;
      animation: fadeInDown 1s ease 0.2s backwards;
    }

    @keyframes fadeInDown {
      from {
        opacity: 0;
        transform: translateY(-30px);
      }
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    .sky {
      position: relative;
      width: 100%;
      height: 80vh;
      overflow: hidden;
    }

    /* Cloud Styles */
    .cloud {
      position: absolute;
      background: rgba(255, 255, 255, 0.8);
      border-radius: 100px;
      box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
    }

    .cloud::before,
    .cloud::after {
      content: '';
      position: absolute;
      background: rgba(255, 255, 255, 0.8);
      border-radius: 100px;
    }

    /* Cloud 1 - Large Fluffy */
    .cloud-1 {
      width: 200px;
      height: 60px;
      top: 10%;
      animation: float 20s linear infinite;
    }

    .cloud-1::before {
      width: 100px;
      height: 80px;
      top: -40px;
      left: 20px;
    }

    .cloud-1::after {
      width: 120px;
      height: 70px;
      top: -30px;
      right: 20px;
    }

    /* Cloud 2 - Medium */
    .cloud-2 {
      width: 150px;
      height: 50px;
      top: 25%;
      animation: float 25s linear infinite;
      animation-delay: -5s;
    }

    .cloud-2::before {
      width: 80px;
      height: 60px;
      top: -30px;
      left: 15px;
    }

    .cloud-2::after {
      width: 90px;
      height: 55px;
      top: -25px;
      right: 15px;
    }

    /* Cloud 3 - Small */
    .cloud-3 {
      width: 100px;
      height: 40px;
      top: 40%;
      animation: float 15s linear infinite;
      animation-delay: -10s;
    }

    .cloud-3::before {
      width: 60px;
      height: 50px;
      top: -25px;
      left: 10px;
    }

    .cloud-3::after {
      width: 70px;
      height: 45px;
      top: -20px;
      right: 10px;
    }

    /* Cloud 4 - Extra Large */
    .cloud-4 {
      width: 250px;
      height: 70px;
      top: 55%;
      animation: float 30s linear infinite;
      animation-delay: -15s;
    }

    .cloud-4::before {
      width: 120px;
      height: 90px;
      top: -45px;
      left: 30px;
    }

    .cloud-4::after {
      width: 140px;
      height: 80px;
      top: -35px;
      right: 30px;
    }

    /* Cloud 5 - Tiny */
    .cloud-5 {
      width: 80px;
      height: 35px;
      top: 70%;
      animation: float 12s linear infinite;
      animation-delay: -3s;
    }

    .cloud-5::before {
      width: 50px;
      height: 45px;
      top: -22px;
      left: 8px;
    }

    .cloud-5::after {
      width: 55px;
      height: 40px;
      top: -18px;
      right: 8px;
    }

    /* Cloud 6 - Wide */
    .cloud-6 {
      width: 180px;
      height: 55px;
      top: 15%;
      animation: float 22s linear infinite;
      animation-delay: -18s;
    }

    .cloud-6::before {
      width: 90px;
      height: 70px;
      top: -35px;
      left: 18px;
    }

    .cloud-6::after {
      width: 100px;
      height: 65px;
      top: -30px;
      right: 18px;
    }

    /* Cloud 7 - Puffy */
    .cloud-7 {
      width: 140px;
      height: 45px;
      top: 35%;
      animation: float 18s linear infinite;
      animation-delay: -8s;
    }

    .cloud-7::before {
      width: 75px;
      height: 65px;
      top: -32px;
      left: 12px;
    }

    .cloud-7::after {
      width: 85px;
      height: 60px;
      top: -28px;
      right: 12px;
    }

    /* Cloud 8 - Compact */
    .cloud-8 {
      width: 120px;
      height: 42px;
      top: 60%;
      animation: float 16s linear infinite;
      animation-delay: -12s;
    }

    .cloud-8::before {
      width: 65px;
      height: 55px;
      top: -28px;
      left: 10px;
    }

    .cloud-8::after {
      width: 75px;
      height: 50px;
      top: -24px;
      right: 10px;
    }

    @keyframes float {
      0% {
        left: -300px;
        opacity: 0;
      }
      10% {
        opacity: 1;
      }
      90% {
        opacity: 1;
      }
      100% {
        left: calc(100% + 300px);
        opacity: 0;
      }
    }

    /* Animated Colored Clouds */
    .colored-cloud {
      position: absolute;
      filter: blur(40px);
      opacity: 0.4;
      border-radius: 50%;
      animation: colorFloat 25s ease-in-out infinite;
    }

    .colored-cloud-1 {
      width: 300px;
      height: 300px;
      background: #90e0ef;
      top: 10%;
      left: 10%;
      animation-delay: 0s;
    }

    .colored-cloud-2 {
      width: 400px;
      height: 400px;
      background: #caf0f8;
      top: 40%;
      right: 10%;
      animation-delay: -8s;
    }

    .colored-cloud-3 {
      width: 250px;
      height: 250px;
      background: #90e0ef;
      bottom: 20%;
      left: 30%;
      animation-delay: -15s;
    }

    @keyframes colorFloat {
      0%, 100% {
        transform: translate(0, 0) scale(1);
      }
      33% {
        transform: translate(50px, -30px) scale(1.1);
      }
      66% {
        transform: translate(-30px, 50px) scale(0.9);
      }
    }

    /* Info Cards */
    .info-section {
      position: relative;
      z-index: 10;
      max-width: 1200px;
      margin: 0 auto;
      padding: 40px 20px;
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 30px;
    }

    .info-card {
      background: rgba(255, 255, 255, 0.9);
      backdrop-filter: blur(10px);
      border-radius: 20px;
      padding: 30px;
      box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
      text-align: center;
      transition: transform 0.3s ease;
      animation: fadeInUp 1s ease backwards;
    }

    .info-card:nth-child(1) { animation-delay: 0.2s; }
    .info-card:nth-child(2) { animation-delay: 0.4s; }
    .info-card:nth-child(3) { animation-delay: 0.6s; }

    @keyframes fadeInUp {
      from {
        opacity: 0;
        transform: translateY(50px);
      }
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    .info-card:hover {
      transform: translateY(-10px);
    }

    .info-icon {
      font-size: 3rem;
      margin-bottom: 15px;
    }

    .info-title {
      font-size: 1.5rem;
      color: #0077b6;
      font-weight: 700;
      margin-bottom: 10px;
    }

    .info-desc {
      color: #555;
      line-height: 1.6;
      font-size: 1rem;
    }

    /* Sun */
    .sun {
      position: absolute;
      top: 80px;
      right: 100px;
      width: 120px;
      height: 120px;
      background: #ffd60a;
      border-radius: 50%;
      box-shadow: 0 0 40px rgba(255, 214, 10, 0.6),
                  0 0 80px rgba(255, 214, 10, 0.4);
      animation: sunPulse 4s ease-in-out infinite;
      z-index: 1;
    }

    @keyframes sunPulse {
      0%, 100% {
        transform: scale(1);
        box-shadow: 0 0 40px rgba(255, 214, 10, 0.6),
                    0 0 80px rgba(255, 214, 10, 0.4);
      }
      50% {
        transform: scale(1.05);
        box-shadow: 0 0 60px rgba(255, 214, 10, 0.8),
                    0 0 100px rgba(255, 214, 10, 0.5);
      }
    }

    /* Birds */
    .bird {
      position: absolute;
      width: 40px;
      height: 20px;
      animation: flyBird 15s linear infinite;
      z-index: 5;
    }

    .bird::before,
    .bird::after {
      content: '';
      position: absolute;
      width: 20px;
      height: 8px;
      background: #023e8a;
      border-radius: 50%;
      animation: flapWings 0.5s ease-in-out infinite;
    }

    .bird::before {
      left: 0;
      transform-origin: right center;
    }

    .bird::after {
      right: 0;
      transform-origin: left center;
      animation-delay: 0.25s;
    }

    .bird-1 {
      top: 15%;
      animation-delay: 0s;
    }

    .bird-2 {
      top: 30%;
      animation-delay: -5s;
    }

    .bird-3 {
      top: 45%;
      animation-delay: -10s;
    }

    @keyframes flyBird {
      0% {
        left: -50px;
      }
      100% {
        left: calc(100% + 50px);
      }
    }

    @keyframes flapWings {
      0%, 100% {
        transform: rotateY(0deg);
      }
      50% {
        transform: rotateY(60deg);
      }
    }

    @media (max-width: 768px) {
      .header h1 {
        font-size: 2rem;
      }

      .header p {
        font-size: 1rem;
      }

      .sun {
        width: 80px;
        height: 80px;
        right: 40px;
        top: 60px;
      }

      .sky {
        height: 60vh;
      }

      .info-section {
        grid-template-columns: 1fr;
      }
    }