How can CSS be utilized to create a large structure without using frames in PHP development?

To create a large structure without using frames in PHP development, CSS can be utilized to create a layout that includes header, sidebar, main content, and footer sections. This can be achieved by using CSS flexbox or grid layout to structure the different sections on the webpage.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Large Structure Without Frames</title>
    <style>
        body {
            display: flex;
            flex-direction: column;
            min-height: 100vh;
            margin: 0;
            padding: 0;
        }

        header, footer {
            background: #333;
            color: #fff;
            text-align: center;
            padding: 10px;
        }

        main {
            flex: 1;
            padding: 20px;
        }

        aside {
            background: #f4f4f4;
            padding: 10px;
        }

    </style>
</head>
<body>
    <header>
        <h1>Header</h1>
    </header>
    
    <div class="content">
        <aside>
            <h2>Sidebar</h2>
            <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit.</p>
        </aside>
        
        <main>
            <h2>Main Content</h2>
            <p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nulla feugiat, sem a aliquam ultricies, nunc libero pharetra turpis, nec fringilla urna neque nec tellus.</p>
        </main>
    </div>

    <footer>
        <p>Footer</p>
    </footer>
</body>
</html>