JSFiddle - React, Tailwind, and code Playground

by avrahamcool

HTML

<div id="cover"></div>

CSS

* /*Remove all the default margin and padding*/
{
    margin: 0;
    padding: 0;
}
html, body /*so it'll work when you specify 100% height on element*/
{
    height: 100%;
}

#cover {
    background-color: #ff0000;
    height: 100%;
    opacity: 0.4;
    width: 100%;
}