JSFiddle - React, Tailwind, and code Playground

by Max Sinev

HTML

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

CSS

.triangle {
  width: 0;
  height: 0;
  border: 5px solid black;
  border-left-color: transparent;
  border-top-color: transparent;
  position: absolute;
}

.wrapper {
  width: 100px;
  height: 100px;
  position: relative;
  background-color: #ccc;
}