<body>
  <div class="parent1">
    <div class="box1">
      <div class="box2">
      </div>  
    </div>
  </div>
  <div class="parent2">
    <div class="box3">
      </div>  
    </div>
  </div>
</body>
body{
      margin: 0;
    }
    .parent1, .parent2{
      background: yellow;
      display: flex;
      align-items: center;
      justify-content: center;
      height: 100vh;
    }

.box1{
      width: 20%;
      height: 40vh;
      background: red;
      position: relative;
    }

.box2{
      background: blue;
      width: 20%;
      height: 40vh;
      position: fixed;
      top: 50px;
      right: 50px;
    }

.box3{
    width: 20%;
    height: 40vh;
    background: green;
    position: relative;
    }

External CSS

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External JavaScript

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