JSFiddle - React, Tailwind, and code Playground

HTML

<div class="t">2</div>

CSS

.t {
  background: #333;
  padding: 5px 12px;
  font-size: 12px;
  display: inline;
  margin-left: 15px;
  border-radius: 2px;
  position: relative;
  color: #fff;
}

.t:after,
.t:before {
  right: 100%;
  top: 50%;
  border: solid transparent;
  content: " ";
  height: 0;
  width: 0;
  position: absolute;
  pointer-events: none;
}

.t:after {
  border-color: rgba(48, 48, 48, 0);
  border-right-color: #333;
  border-width: 11px;
  margin-top: -11px;
}