A pure CSS drop-down solution.

Dropdown.html

<style>
	span p{
		cursor:pointer;
	}
	span ul{
		transition: all 0.5s ease;
		list-style:none;
		height:0px;
		padding:0;
		overflow:hidden;
		opacity:0;
		border:1px solid #ddd;
		width:300px;
	}
	span ul li{
		border-bottom:1px solid #ddd;
		padding:10px;
	}
	span ul li:last-of-type{
		border:none;
	}
	span:hover ul{
		height:118px;
		opacity:1;
	}
</style>

<span>
	<p>Dropdown with Pure CSS</p>
	<ul>
		<li>Take</li>
		<li>That</li>
		<li>Bootstrap</li>
	</ul>
</span>