JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block"></div>

CSS

body, html {
    height: 100%;
    margin: 0;
}

.block {
    height: 100%;
    background: linear-gradient(top ,red 70%, green 30%);
    background: -webkit-linear-gradient(top ,red 70%, green 30%);
    background: -moz-linear-gradient(top ,red 70%, green 30%);
    background: -o-linear-gradient(top ,red 70%, green 30%);
}