JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="overlay"><h1>Hello World</h1></div>
</div>

CSS

.container {
    background: url(http://www.mrwallpaper.com/wallpapers/daisies-green-background.jpg) no-repeat center center fixed;
	background-size: cover; 
    width: 500px;
    height: 500px;
}

.overlay {

     background-color: rgba(0,0,0,0.8);
    width: 100%;
    height: 100%;
}

h1 {
     
    color: #FFFFFF;
}