JSFiddle - React, Tailwind, and code Playground

HTML

<div class="page_login">
    <div>vertical-align:center; text-align:center</div>
</div>

CSS

html, body {
    height:100%;
}

.page_login {
	display:flex;
	height:100%;
	width:100%;
	background:#303030;
}

.page_login > div {
	margin:auto;
	background:#fff;
	min-height:100px;
	width:200px;
}