index.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">
    <link href="style.css" rel="stylesheet" type="text/css">
    <title>Document</title>
</head>
<body>
    <div class="heading">
    <header>
        <h1>Etch-a-Sketch</h1>
    </header>
</div>

    
    <div class=btn-container>
        <button class="btn" id="grid-size">Grid size</button>
        <button class="btn" id="clear">clear</button>
        <button class="btn" id="classic">classic</button>
        <button class="btn" id="rgb">RGB</button>
        <button class="btn" id="custom">custom</button>
        <button class="btn" id="invert">Invert</button>
        </div>
    <script defer src="beeteretch.js"></script>
</body>
</html>