Live Code Editor Version 2.0

css-navigation-hor-child RUN

<!DOCTYPE html>
<html>
	<head>
		<style>
			ul {
				list-style-type: none;
				margin: 0;
				padding: 0;
				overflow: hidden;
				background-color: #f0f0f0;
			}

li {
				float: left;
			}

li a, .droppr {
				display: inline-block;
				color: black;
				text-align: center;
				padding: 14px 16px;
				text-decoration: none;
			}

li a:hover, .dropdown:hover .dropbtn {
				background-color: white;
			}

li.dropdown {
				display: inline-block;
			}

.dropdown-content {
				display: none;
				position: absolute;
				background-color: #f9f9f9;
				min-width: 160px;
				box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
				z-index: 1;
			}

.dropdown-content a {
				color: black;
				padding: 12px 16px;
				text-decoration: none;
				display: block;
				text-align: left;
			}

.dropdown-content a:hover {background-color: white}
			.dropdown:hover .dropdown-content {
				display: block;
			}
		</style>
	</head>
	<body>
		<ul>
			<li><a href="#">WEBMASTER</a></li>
			<li><a href="#">LẬP TRÌNH</a></li>
			<li class="dropdown">
				<a href="#" class="droppr">DATABASE</a>
				<div class="dropdown-content">
					<a href="#">SQL</a>
					<a href="#">ORACLE</a>
					<a href="#">MONGODB</a>
				</div>
			</li>
		</ul>
	</body>
</html>