JSFiddle - React, Tailwind, and code Playground

HTML

<p class="demo">demo!</p>

CSS

p.demo:before {
  content:'';
  position: absolute;
  width: 0;
  height: 0;
  left: 30px;
  top: 100px;
  border: 25px solid;
  border-color: grey transparent transparent grey;
}

p.demo {
  position: relative;
  width: 200px;
  height: 100px;
  text-align: center;
  line-height: 100px;
  background-color: #fff;
  border: 8px solid grey;
  -webkit-border-radius: 29px;
  -moz-border-radius: 29px;
  border-radius: 29px;
  -webkit-box-shadow: 3px 3px 4px grey;
  -moz-box-shadow: 3px 3px 4px grey;
  box-shadow: 3px 3px 4px grey;
}
p.demo:after {
  content: ' ';
  position: absolute;
  width: 0;
  height: 0;
  left: 38px;
  top: 100px;
  border: 15px solid;
  border-color: #fff transparent transparent #fff;
}