code_for_css_1.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>CSS PART 1</title>
    <link rel="stylesheet" href="CSS_1.css">
    <style>
        button {
            background-color:blue;
        }
    </style>
</head>
<body>
    <div id="box">
        <h1>Heading</h1>
        <p>This is a paragraph in a division. And the background color of this division is set to blue.</p>
    </div>
    <h1 class="heading">Heading 1</h1>
    <h2 class="heading">Heading 2</h2>
    <h3 class="heading">Heading 3</h3>

    <button style="background-color:pink">Click me</button>

    <h1 id="hone">This is a heading</h1>

    <div id="outer">
        <p>This is a paragraph in the outer div which is not included in the inner div.</p>
        <div id="inner">
            <p>This is a paragraph in the outer div which is included in the inner div.</p>
        </div>
    </div>
</body>
</html>