header.php

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>UAGC Courses</title>
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0-alpha1/css/bootstrap.min.css" integrity="sha384-r4NyP46KrjDleawBgD5tp8Y7UzmLA05oM1iAEQ17CSuDqnUK2+k9luXQOfXJCJ4I" crossorigin="anonymous">
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/5.0.0-alpha1/js/bootstrap.min.js" integrity="sha384-oesi62hOLfzrys4LxRF63OJCXdXDipiYWBnvTl9Y9/TRlw5xlKIEHpNyvvDShgf/" crossorigin="anonymous"></script>
    <script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
</head>
<body>
<header class="main-header">
    <h1>UAGC Student Course Portal</h1>
    <nav>
        <ul>
            <li><a href="index.php">Home</a></li>
            <?php if (isset($_SESSION['user_id'])): ?>
                <li><a href="dashboard.php">Dashboard</a></li>
                <li><a href="logout.php">Logout</a></li>
            <?php else: ?>
                <li><a href="login.php">Login</a></li>
                <li><a href="registration.php">Registration</a></li>
            <?php endif; ?>
        </ul>
    </nav>
</header>