JSFiddle - React, Tailwind, and code Playground

HTML

<div class="ramka_outer">
            <div class="ramka"></div>
        </div>

CSS

body{
margin:0;
padding:0;
height:100%;
background:#ccc;
}

.ramka_outer{
margin:100px;    
background:#000;
display:inline-block;
border:3px double #fff;
}

.ramka{
width:300px;
height:300px;
background:#ccc;
}