JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    
</div>

CSS

div {
    height: 400px;
    background: blue;
    position: relative;
    overflow: hidden;
}

div:before {
    content: " ";
    position: absolute;
    width: 0;
    height: 0;
    right: 100%;
    bottom: -2000px;
    margin-left: -2000px;
    border-width: 2000px;
    border-style: solid;
    border-color: white transparent transparent;
}