adaptive

by Valentin Sarychev

HTML

<div class="inline-block">
  <div class="adaptive">
  </div>
</div>

CSS

.inline-block {
  display: inline-block;
}

.adaptive {
  display: block;
  background: red;
  height: 20px;
  width: 100%;
}

/* растягивает родительский inline-block */
.adaptive::after {
  display: table;
  content: '';
  table-layout: fixed;
  width: 100%;
}