CodePen Embed - Jwjbzj

<div class="outer">
  <div class="box"></div>  
</div>

<p>実際の幅は240px</p>

.outer {
  width: 200px;
  background: #c0ffee;
}

.box {
  width: 100%;
  height: 40px;
  border: 1px solid #999;
  padding: 20px;
}

This Pen is owned by natsumi on CodePen.

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