JSFiddle - React, Tailwind, and code Playground

HTML

<div></div>

CSS

div {
    height: 100px;
    width: 200px;
    overflow: hidden;
    position: relative;
}
div:before {
    height: inherit;
    width: inherit;
    position: absolute;
    content: "";
    border-radius: 100px 100px 0 0;
    background-color: crimson;
    -webkit-transform-origin: 50% 100%;
    -moz-transform-origin: 50% 100%;
    -ms-transform-origin: 50% 100%;
    transform-origin: 50% 100%;
    -webkit-transform: rotate(140deg);
    -moz-transform: rotate(140deg);
    -ms-transform: rotate(140deg);
    transform: rotate(140deg);
}