html cómo configurar la clase

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
	<!-- you should write class and set the correct name for finding your codes easily example i will give it a name like nav-bar -->
    <div class="nav-bar"></div>
    <!-- now you can use your class to make it looks better using css and js -->
</body>
</html>
Friendly Fox