JSFiddle - React, Tailwind, and code Playground

HTML

<div class="a">
    <div class="b">Hello World</div>
</div>

CSS

.a
{
    background: rgba(25, 25, 25, .1);
    color: white;
    font-size: 20px;
    position: fixed;
    top: 10%;
    bottom: 10%;
    left: 10%;
    right: 10%;
}

.b
{
    background-color:red;
    color: white;
    font-size: 20px;
    position: fixed;
    width:100px;
    height:50px;
    left:100px;
    top:100px;
}
body, html {
    height: 100%;

}
body {
    background: -moz-linear-gradient(to bottom, #FFFFFF, #0099ff);
    background: linear-gradient(to bottom, #FFFFFF, #0099ff);
}