JSFiddle - React, Tailwind, and code Playground

HTML

<div class="triangle"></div>

CSS

/* basic styles */
 div {
    text-align: center;
    color: #fff;
    font-size: 1.125em;
    margin: -50px 0 0 50px;
}
/* draw triangle */
 div.triangle {
    position: absolute;
    border: 110px solid transparent;
    border-bottom: 126px solid #D30000;
}
/* add text */
 div.triangle:after {
    content:"here is a triangle";
    position: absolute;
    bottom: -126px;
    right: -126px;
    left: -126px;
}