<div class="sample">
  <p>親要素</p>
  <div class="sample__content">
    <p>子要素</p>
  </div>
  <p>親要素</p>
</div>
.sample{
  max-width:500px;
  margin:0 auto;
  background:#000;
  color:#fff;
  text-align:center;
}

.sample__content{
  background:#00f;
  max-width:600px;
  margin:0 -50px;
}

External CSS

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External JavaScript

This Pen doesn't use any external JavaScript resources.