JSFiddle - React, Tailwind, and code Playground

HTML

<div id="login_container">
		<div class="login"></div>
		<div class="login"></div>
		<div class="login"></div>
</div>

CSS

#login_container {
  display: flex;
	align-items: center;
  justify-content: center;
  height:100%;
}
body,html {
  height:100%;
}
.login {
	background-color: #008000;
	width: 100px;
	height: 100px;
	margin: 2px;
}