<div class="wrap">
  <div class="box">margin: 0 auto;<br>で要素を左右中央に並べる</div>
</div>
.box {
  width: 200px;
  height: 100px;
  margin: 0 auto;
  border: 1px solid black;
  background-color: #008dab;
  color: white;
}

.wrap {
  min-width: max-content;
  margin: 0;
  padding: 10px;
  border: 1px solid gray;
  background-color: #ddd;
}
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