index.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <link rel="stylesheet" href="main.css" type="text/css" />
    <title>Document</title>
</head>
<body>
    <nav class="navDefault">
        <div class="dropdown">
            <button>Dropdown</button>
            <ul class="dropdownMenu">
                <li class="dropdownItem"><a href="#" class="dropdownLink">Link</a></li>
                <li class="dropdownItem"><a href="#" class="dropdownLink">Link</a></li>
                <li class="dropdownItem"><a href="#" class="dropdownLink">Link</a></li>
                <li class="dropdownItem"><a href="#" class="dropdownLink">Link</a></li>
            </ul>
        </div>
    </nav> 
</body>
</html>