JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#">Reveal</a>

<div class="arrow_box">
    content<br>
    content<br>
    content<br>
    content<br>
    content<br>
    content<br>
</div>

CSS

.arrow_box {
	position: relative;
    display: none;
	background: #88b7d5;
	border: 4px solid #c2e1f5;
    padding: 20px;
    margin-top: 100px;
    width: 300px;
}
.arrow_box:after, .arrow_box:before {
	bottom: 100%;
	left: 50%;
	border: solid transparent;
	content: " ";
	height: 0;
	width: 0;
	position: absolute;
	pointer-events: none;
}

.arrow_box:after {
	border-color: rgba(136, 183, 213, 0);
	border-bottom-color: #88b7d5;
	border-width: 30px;
	margin-left: -30px;
}
.arrow_box:before {
	border-color: rgba(194, 225, 245, 0);
	border-bottom-color: #c2e1f5;
	border-width: 36px;
	margin-left: -36px;
}

JavaScript

$(function(){
    $('a').click(function(e){
        e.preventDefault();
        $('.arrow_box').slideDown();
    });
});