<?php
    $loader = new \Twig\Loader\FilesystemLoader('templates');
    $twig = new \Twig\Environment($loader, [
        'cache' => '/path/to/compilation_cache',
    ]);

    if (isset($_GET["page"]) && $_GET["page"] != "") {
        echo $twig->render('page.html', ['title' => $_GET["page"]]);
    }
?>