JSFiddle - React, Tailwind, and code Playground
by ncapito
HTML
<br />
<div class="container">
<center>Test Container</center>
</div>
<br>
</br>
<div class='container'>
<div class='before'></div>
<div class='after'></div>
</div>
CSS
.container {
margin-left: 15px;
width: 100px;
position: relative;
border: solid transparent;
border-color: transparent transparent black transparent;
border-style: solid;
border-width: 1px;
}
.container:after,after {
content:'';
display: block;
position: absolute;
left: 50%;
top: 100%;
width: 0;
height: 0;
border-color: white transparent transparent transparent;
border-style: solid;
border-width: 7px;
margin-left: -7px;
}
.container:before,before {
content:'';
display: block;
position: absolute;
top: 100%;
left: 50%;
width: 0;
height: 0;
border-color: black transparent transparent transparent;
border-style: solid;
border-width: 8px;
margin-left: -8px;
}