source: lightning/13.1.1/sidebar-post.php

<?php
if ( is_active_sidebar( 'common-side-top-widget-area' ) ) {
        dynamic_sidebar( 'common-side-top-widget-area' );
}

// Display post type widget area
$widdget_area_name = 'post-side-widget-area';
if ( is_active_sidebar( $widdget_area_name ) ) {
        dynamic_sidebar( $widdget_area_name );
} else { ?>

<?php
$post_loop = new WP_Query(
        array(
                'post_type'              => 'post',
                'posts_per_page'         => 10,
                'no_found_rows'          => true,
                'update_post_meta_cache' => false,
                'update_post_term_cache' => false,
        )
);
?>

<?php if ( $post_loop->have_posts() ) : ?>
<aside class="widget widget_postlist">
<h1 class="subSection-title"><?php echo __( 'Recent posts', 'lightning' ); ?></h1>
<?php
while ( $post_loop->have_posts() ) :
        $post_loop->the_post();
?>

  <div class="media">

        <?php if ( has_post_thumbnail() ) : ?>

          <div class="media-left postList_thumbnail">
                <a href="<?php the_permalink(); ?>">
                <?php the_post_thumbnail( 'thumbnail' ); ?>
                </a>
          </div>

        <?php endif; ?>

        <div class="media-body">
          <h4 class="media-heading"><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h4>
          <div class="published entry-meta_items"><?php echo get_the_date(); ?></div>
        </div>
  </div>

<?php endwhile; ?>
</aside>
<?php endif; ?>
<?php wp_reset_query(); ?>

<aside class="widget widget_categories widget_link_list">
<nav class="localNav">
<h1 class="subSection-title"><?php _e( 'Category', 'lightning' ); ?></h1>
<ul>
        <?php wp_list_categories( 'title_li=' ); ?>
</ul>
</nav>
</aside>

<aside class="widget widget_archive widget_link_list">
<nav class="localNav">
<h1 class="subSection-title"><?php _e( 'Archive', 'lightning' ); ?></h1>
<ul>
        <?php
        $args = array(
                'type'      => 'monthly',
                'post_type' => 'post',
        );
        wp_get_archives( $args );
        ?>
</ul>
</nav>
</aside>

<?php
}

if ( is_active_sidebar( 'common-side-bottom-widget-area' ) ) {
        dynamic_sidebar( 'common-side-bottom-widget-area' );
}