JSFiddle - React, Tailwind, and code Playground

by web tiki

HTML

<div></div>
<div class="second"></div>

CSS

body{
    margin:0;
    padding:0;
}
div{
    height:200px;
    background:teal;
    position:relative;
}
.second{
    background:gold;
}

.second:before{
    content:'';
    position:absolute;
    bottom:100%;
    border-left:100vw solid transparent;
    border-bottom: 80px solid gold;
}