<?php
   // If comments are open or we have at least one comment, load up the comment template.
   if ( comments_open() || get_comments_number() ) :
      comments_template();
   endif;
?>

<?php wp_list_comments( array(
        'depth' => '2',
        'callback' => 'better_comments'
) ); ?>

<?php
// . Better Comments
// . ===============

function better_comments( $comment, $args, $depth ) {
    global $post;
    $author_id = $post->post_author;
    $GLOBALS['comment'] = $comment;
    switch ( $comment->comment_type ) :
        case 'pingback' :
        case 'trackback' :
    ?>

    <li id="comment-<?php comment_ID(); ?>" <?php comment_class(); ?>>