<!DOCTYPE html>
<html lang="<?php echo $lang ?? 'en'; ?>">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title><?php echo $subject; ?></title>
    <style>
        body {
            font-family: Arial, sans-serif;
            line-height: 1.6;
            color: #333;
            max-width: 600px;
            margin: 20px auto;
            padding: 20px;
            border: 1px solid #ddd;
            border-radius: 5px;
        }
        .header {
            background-color: #f7f7f7;
            padding: 10px;
            text-align: center;
            border-bottom: 1px solid #ddd;
        }
        .content {
            padding: 20px 0;
        }
        .footer {
            margin-top: 20px;
            padding: 10px;
            background-color: #f7f7f7;
            text-align: center;
            font-size: 0.8em;
            color: #777;
        }
    </style>
</head>
<body>
    <div class="header">
        <h1><?php echo $site_name ?? 'Our Site'; ?></h1>
    </div>
    <div class="content">
        <?php echo $body; ?>
    </div>
    <div class="footer">
        <p>&copy; <?php echo date('Y'); ?> <?php echo $site_name ?? 'Our Site'; ?>. All rights reserved.</p>
    </div>
</body>
</html>