<div class="contentBox">
  <span class="contentBox__item">item</span>
</div>
.contentBox{
  display:table;
  table-layout:fixed;
  width:100%;
  height:200px;
  background:#ddd;
  text-align:center;
}
.contentBox__item{
  display:table-cell;
  vertical-align:middle;
}

External CSS

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External JavaScript

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