sidebar.php

<!-- sidebar -->
<div class="single-sidebar">
	<div class="wrapper">
		<?php if (is_active_sidebar('sidebar-1')) { ?>
			<div id="sidebar-one">
				<?php dynamic_sidebar('sidebar-1'); ?>
			</div>
		<?php } ?>
	</div>
	<div class="group-heading">
		<h3>
			<?php
			$cat = get_theme_mod('side_category_5');
			$cat = get_category($cat);
			$cat_post = '';
			if (is_wp_error($cat)) { // category is not set
				$cat_post = 'uncategorized';
			} else {
				$cat_post = $cat->slug;
				echo $cat->name;
			}

			if (empty($cat_post)) { //check if category is set
				$cat_post = 'uncategorized';
			}

			?>
			<!-- Popular Posts -->
		</h3>
	</div>
	<div class="sidebar">
		<div class="popular-post-container">
			<div class="post-group popular-post">
				<?php
				// pull 4 posts 
				$args = array(
					'post_type' => 'post',
					'posts_per_page' => '4',
					'category_name' => $cat_post,
				);
				$query = new WP_Query($args);
				?>

				<?php if ($query->have_posts()) : while ($query->have_posts()) : $query->the_post(); ?>

						<?php
						if (!is_sticky()) {
							get_template_part('template-parts/posts/post', 'article');
						}
						?>

					<?php endwhile;
					wp_reset_postdata();
				else : ?>
					<p><?php _e('Sorry, no posts matched your criteria.'); ?></p>
				<?php endif; ?>
			</div>
		</div>
	</div>
	<div class="wrapper">
		<?php if (is_active_sidebar('sidebar-2')) { ?>
			<div id="sidebar-two">
				<?php dynamic_sidebar('sidebar-2'); ?>
			</div>
		<?php } ?>
	</div>
</div>