JSFiddle - React, Tailwind, and code Playground

HTML

<div class='user-nav'>
    <button class="drop-menu-button">Menu</button>
</div>
<div class='drop-menu'>
    <ul>
        <li><a href='#'>My Profile</a></li>
        <li><a href='#'>Logout</a></li>
    </ul>
</div>

CSS

.user-nav {
    height: 50px;
    background-color: black;
}

.drop-menu {
    display: none;
    position: relative;
    height: 60px;
    top: -20px;
}

.drop-menu ul::before {
    content: '';
    width: 0;
    height: 0;
    position: absolute;
    top: -30px;
    left: 30px;
    border-width: 15px;
    border-color: transparent transparent red transparent;
    border-style: solid;
}

.drop-menu ul {
    background-color: red;
    position: relative;
    top: 20px;
    z-index: 999;
}

JavaScript

$('.drop-menu-button').click(function() {
    $('.drop-menu').slideToggle(1000);
});