Answers for "how to div to center"

centre div

<div class="container">
  <div class="child"></div>
</div>
.container {
  ...
  display: flex;
  justify-content: center;
  align-items: center;
}

how to center a div

.MyDiv{
  	display: block;
  	margin-left: auto;
	margin-right: auto;
}

how to horizontal center a div in css

#inner {
  width: 50%;
  margin: 0 auto;
}