JSFiddle - React, Tailwind, and code Playground

HTML

<ul class="menu-dropdown">
	<li>
		<a href="#">Parent</a>
		<ul class="dropdown">
			<li><a href="#">Dropdown1</a></li>
			<li><a href="#">Dropdown2</a></li>
			<li><a href="#">Dropdown3</a></li>
		</ul>
	</li>
</ul>

CSS

ul,li {
	padding: 0;
	margin: 0;
}
.dropdown {
	display: none;
	position: absolute;
	top: 100%;
}
.menu-dropdown>li {
	position: relative;
    display: inline-block;
}
.menu-dropdown>li:hover .dropdown {
	display: block;
}