body {
    background: #111;
    color: white;
    font-family: Arial;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    padding: 20px;
}

.card {
    background: #222;
    padding: 10px;
    border-radius: 10px;
    text-align: center;
}

.car-img {
    width: 100%;
    height: 180px;
    object-fit: cover;
}

button {
    margin: 5px;
    padding: 5px 10px;
    background: magenta;
    border: none;
    color: white;
    cursor: pointer;
}
.nav {
    display: flex;
    justify-content: space-between;
    padding: 10px 20px;
}

.nav a {
    color: white;
    margin-left: 10px;
    text-decoration: none;
}

.nav a:hover {
    color: magenta;
}

<div class="nav">

<div>
    <a href="index.php">?? Domů</a>
</div>

<div>
<?php if (!isLoggedIn()): ?>
    <a href="login.php">Přihlásit</a>
    <a href="register.php">Registrace</a>
<?php else: ?>

    <?php if (isAdmin()): ?>
        <a href="admin/dashboard.php">Admin</a>
    <?php else: ?>
        <a href="profile.php">Profil</a>
    <?php endif; ?>

    <a href="logout.php">Odhlásit</a>

<?php endif; ?>
</div>

</div>