JSFiddle - React, Tailwind, and code Playground

HTML

<div id='container'>
    <div id='bubble'>
           ABC
    </div>
</div>

CSS

#container
{
    height:500px;
    background-color:#Febb68;
    padding:30px;
}
#bubble
{
	height:200px;	
    width:200px;
	padding: 50px 60px 0;	
	position: relative;
	z-index: 10;
	border-radius: 30px 0;
	background: rgba(255,255,255,.85);
	box-shadow: 0 0 10px 1px #944;
	margin-bottom: 55px;
}
#bubble:after {
	content: "";
	position: absolute;
	top: 100%;
	left: 0;
	width: 0;
	height: 0;
	border-top: 85px solid rgba(255,255,255,0.85);
	border-right: 85px solid transparent;
	border-left: 0px solid transparent;
}