[käptn]

CSS:

.innerCentered {
  text-align: center;
}
.centered {
  margin-left: auto;
  margin-right: auto;
}
.grayBox {
  border: 1px solid #000;
  width: 200px;
  background: #ccc;
}

HTML:

<div class="innerCentered">
  <div class="grayBox centered">
    BLA
  </div>
</div>

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