JSFiddle - React, Tailwind, and code Playground

HTML

<div class="bloc">
  <div class="row">row1</div>
</div>

CSS

.bloc {
	width: 100%;
	height: auto;
	margin: 40px auto auto auto; /* Centraliser le container sur la page */
	position: relative;
	text-align: center;
  background:red;
}

.row {
	width: 90%;
	height: auto;
	margin: 0px auto auto auto; /* Centraliser la ligne sur le container */
	vertical-align: middle;
  background:blue;
}