What are the potential drawbacks of using an old table layout in PHP instead of modern CSS?

Using an old table layout in PHP instead of modern CSS can lead to less responsive and flexible designs, slower page loading times, and difficulty in maintaining and updating the code. To solve this issue, it is recommended to separate the HTML structure from the styling by using CSS for layout and design.

<!DOCTYPE html>
<html>
<head>
    <title>Modern CSS Layout</title>
    <style>
        body {
            font-family: Arial, sans-serif;
            background-color: #f0f0f0;
            margin: 0;
            padding: 0;
        }
        .container {
            width: 80%;
            margin: 0 auto;
            background-color: #fff;
            padding: 20px;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
        }
        .header {
            background-color: #333;
            color: #fff;
            padding: 10px;
            text-align: center;
        }
        .content {
            padding: 20px;
        }
        .footer {
            background-color: #333;
            color: #fff;
            padding: 10px;
            text-align: center;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="header">
            <h1>Welcome to Modern CSS Layout</h1>
        </div>
        <div class="content">
            <p>This is a modern CSS layout example.</p>
        </div>
        <div class="footer">
            <p>© 2021 Modern CSS Layout</p>
        </div>
    </div>
</body>
</html>