JSFiddle - React, Tailwind, and code Playground

HTML

<div>&nbsp;</div>

CSS

div {
    margin: 20px;
    width: 250px;
    height: 250px;
    -moz-border-radius: 15px;
    -webkit-border-radius: 15px;
    -khtml-border-radius: 15px;
    border-radius: 15px;
    background-color: #4c66a1;
    border: 2px solid #4c66a1;
}