Custom Comment Template

function custom_comment_template($comment, $args, $depth) {
    ?>
    <li <?php comment_class(); ?> id="comment-<?php comment_ID(); ?>">
        <div class="comment-body">
            <?php echo get_avatar($comment, 60); ?>
            <div class="comment-content">
                <h4 class="comment-author"><?php comment_author(); ?></h4>
                <div class="comment-metadata">
                    <time datetime="<?php comment_time('c'); ?>">
                        <?php printf(__('%1$s at %2$s', 'textdomain'), get_comment_date(), get_comment_time()); ?>
                    </time>
                </div>
                <?php comment_text(); ?>
                <?php comment_reply_link(array_merge($args, array('depth' => $depth, 'max_depth' => $args['max_depth']))); ?>
            </div>
        </div>
    <?php
}

// Usage in comments.php
wp_list_comments(array(
    'callback' => 'custom_comment_template'
));