JSFiddle - React, Tailwind, and code Playground

HTML

<div class="shape"></div>

CSS

.shape {
    position: relative;
    width: 78px;
    height:30px;
    background:#3a93d0;
}

.shape:after {
    content: '';
    display: block;
    position: absolute;
    top: 100%;
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 25px 39px 0 39px;
    border-color: #3a93d0 transparent transparent transparent;
}