CSS3实现上下拉长加载动画效果

上下拉长加载动画效果

<!DOCTYPE html>
<html>
  <head>
    <style>
      .container {
        display: flex;
        justify-content: center;
        align-items: center;
        width: 150px;
        height: 150px;
        margin: 50px auto;
      }

      .rectangle {
        width: 20px;
        height: 50px;
        background-color: #02A0E9;
      }

      .rectangle ~ .rectangle {
        margin-left: 10px;
      }

      .rectangle:nth-child(1) {
        animation: stretch 1.5s ease-in-out infinite 0.1s;
      }

      .rectangle:nth-child(2) {
        animation: stretch 1.5s ease-in-out infinite 0.3s;
      }

      .rectangle:nth-child(3) {
        animation: stretch 1.5s ease-in-out infinite 0.5s;
      }

      .rectangle:nth-child(4) {
        animation: stretch 1.5s ease-in-out infinite 0.7s;
      }

      .rectangle:nth-child(5) {
        animation: stretch 1.5s ease-in-out infinite 0.9s;
      }

      @keyframes stretch {
        0% {
          height: 50px;
        }
        50% {
          height: 120px;
        }
        100% {
          height: 50px;
        }
      }
    </style>
  </head>
  <body>
    <div class="container">
      <div class="rectangle"></div>
      <div class="rectangle"></div>
      <div class="rectangle"></div>
      <div class="rectangle"></div>
      <div class="rectangle"></div>
    </div>
  </body>
</html>