JSFiddle - React, Tailwind, and code Playground
HTML
<br/><br/><br/><br/>
<div class="bubble"></div>
CSS
.bubble
{
position: relative;
width: 275px;
height: 40px;
padding: 5px;
background: #C00006;
-webkit-border-radius: 14px;
-moz-border-radius: 14px;
border-radius: 14px;
}
.bubble:after
{
content: '';
position: absolute;
border-style: solid;
border-width: 0 19px 120px;
border-color: #C00006 transparent;
display: block;
width: 0;
z-index: 1;
margin-left: -49px;
top: -79px;
left: 95%;
-ms-transform: rotate(50deg);
-webkit-transform: rotate(50deg);
transform: rotate(50deg);
}