a5.html

<!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>

    <!-- External CSS file is linked using link tag -->
    <link type="text/css" rel="stylesheet" href="a5.css" >
</head>
<body>    

    <h1 id="aa">Some text...</h1>

    <h1 id="bb">Some more text...</h1>
    
    <h1 id="cc">Some more more text...</h1>

</body>
</html>