function handle_festival_filter() {
    // ... (le début de la fonction avec la récupération des filtres ne change pas)
    $region = isset($_POST['region']) ? stripslashes(sanitize_text_field($_POST['region'])) : '';
    $department_code = isset($_POST['departement']) ? sanitize_text_field($_POST['departement']) : '';
    $month = isset($_POST['mois']) ? intval($_POST['mois']) : '';

    $args = array(
        'post_type' => 'festival',
        'posts_per_page' => -1,
        'meta_query' => array('relation' => 'AND'),
        'orderby' => 'meta_value',
        'meta_key' => 'date_debut',
        'order' => 'ASC'
    );
    
    // Si aucun filtre n'est appliqué, on affiche les festivals à venir
    if (empty($region) && empty($department_code) && empty($month)) {
        $args['meta_query'][] = array(
            'key' => 'date_fin',
            'value' => date('Ymd'),
            'compare' => '>=',
            'type' => 'DATE'
        );
    }

    // ... (le reste de la logique de filtrage ne change pas)
    if (!empty($region)) {
        $args['meta_query'][] = array( 'key' => 'region', 'value' => $region, 'compare' => 'LIKE' );
    }
    if (!empty($department_code)) {
        $args['meta_query'][] = array( 'key' => 'codedep', 'value' => $department_code, 'compare' => '=' );
    }
    if (!empty($month)) {
        $year = date('Y');
        $start_of_month = date('Ymd', mktime(0, 0, 0, $month, 1, $year));
        $end_of_month = date('Ymt', mktime(0, 0, 0, $month, 1, $year));
        $args['meta_query'][] = array('relation' => 'OR',
            array('key' => 'date_debut', 'value' => array($start_of_month, $end_of_month), 'compare' => 'BETWEEN', 'type' => 'DATE'),
            array('key' => 'date_fin', 'value' => array($start_of_month, $end_of_month), 'compare' => 'BETWEEN', 'type' => 'DATE'),
            array('relation' => 'AND',
                array('key' => 'date_debut', 'value' => $start_of_month, 'compare' => '<=', 'type' => 'DATE'),
                array('key' => 'date_fin', 'value' => $end_of_month, 'compare' => '>=', 'type' => 'DATE')
            )
        );
    }
    
    $query = new WP_Query($args);
    $festivals_by_month = [];

    if ($query->have_posts()) {
        while ($query->have_posts()) {
            $query->the_post();
            $date_debut_obj = DateTime::createFromFormat('Ymd', get_field('date_debut'));
            if ($date_debut_obj) {
                // On groupe les festivals par mois/année
                $month_year = $date_debut_obj->format('F Y');
                if (!isset($festivals_by_month[$month_year])) {
                    $festivals_by_month[$month_year] = [];
                }
                $festivals_by_month[$month_year][] = get_post();
            }
        }
    }
    wp_reset_postdata();

    if (!empty($festivals_by_month)) {
        // On utilise les classes CSS de votre agenda actuel 
        echo '<div class="agenda-festivals">';
        foreach ($festivals_by_month as $month_year => $festivals) {
            // Afficher le titre du mois
            echo '<h2 class="mois-titre">' . ucfirst(date_i18n('F Y', strtotime($month_year))) . '</h2>';
            echo '<div class="festivals-grille">'; // Utilise la grille de votre design [cite: 127]
            
            foreach ($festivals as $post) {
                setup_postdata($post);
                $ville = get_field('ville');
                $specificites = get_field('specificites');
                $date_debut_obj = DateTime::createFromFormat('Ymd', get_field('date_debut'));
                
                echo '<div class="festival-carte">'; // La carte de festival [cite: 132]
                
                // Le badge de date à gauche [cite: 146]
                if ($date_debut_obj) {
                    echo '<div class="carte-badge-date">';
                    echo '<span class="jour">' . $date_debut_obj->format('d') . '</span>';
                    echo '<span class="mois">' . date_i18n('M', $date_debut_obj->getTimestamp()) . '</span>';
                    echo '</div>';
                }

                // Le contenu à droite [cite: 171]
                echo '<div class="carte-contenu">';
                echo '<h3><a href="' . get_permalink() . '">' . get_the_title() . '</a></h3>';
                echo '<div class="carte-infos">';
                echo '<span>' . get_field('departement') . '</span>';
                if($specificites){
                    echo '<span class="carte-specificites">' . esc_html($specificites) . '</span>'; // Les spécificités [cite: 196]
                }
                echo '</div>';
                echo '</div>'; // fin carte-contenu
                
                echo '</div>'; // fin festival-carte
            }
            wp_reset_postdata();
            echo '</div>'; // fin festivals-grille
        }
        echo '</div>'; // fin agenda-festivals
    } else {
        echo '<p>Aucun festival ne correspond à votre recherche.</p>';
    }
    
    wp_die();
}