<div class="BFC">
  <div class="box"></div>
</div>
<div class="BFC">
  <div class="box"></div>
</div>
.box {
  width: 100px;
  height: 100px;
  background-color: red;
  margin: 50px;
}
.BFC {
  overflow: hidden;
}

External CSS

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External JavaScript

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