<div>
  <div class="box01">箱</div>
  <div class="box02">箱</div>
</div>
.box01,.box02{
  width: 100px;
}
.box01{
  margin-bottom: 10px;
  background-color: pink;
}
.box02{
  margin-top: -10px;
  background-color: lightblue;
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.