layout.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>layout</title>
    <link rel="stylesheet" href="pet.css">
</head>
<body>
      <div class="container">
        <nav> 
            <h1>Navigation</h1>
        </nav>
        <header>
            <h1>header</h1>
        </header>
        <div class="clear"></div>
      </div>






</body>
</html>