thank you caimin_nwl ??
in my functions.php i added
//EM event Body Class
function add_EM_event_body_class( $classes ) {
global $post;
$EM_Event = em_get_event($post->ID, 'post_id');
$classes[] = $EM_Event->output('#_CATEGORYSLUG');
return $classes;
}
add_filter( 'body_class', 'add_EM_event_body_class' );
and that worked ??
