JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css">
<div class="circle">
    <i class="fa fa-plus icon"></i>
</div>

CSS

.circle {
    border-radius: 50%;
    color: blue;
    background-color: red;
    height:100px;
    width:100px;
    text-align: center;
    line-height: 100px;
}

.icon {
    font-size: 50px;
    vertical-align: middle;
}