pressbooks-aldine/404.php

<?php
/**
 * The template for displaying 404 pages (not found)
 *
 * @link https://codex.wordpress.org/Creating_an_Error_404_Page
 *
 * @package Aldine
 */

get_header(); ?>

	<div id="primary" class="content-area">
		<main id="main" class="site-main">

			<section class="error-404 not-found">
				<header class="page-header">
					<h1 class="page-title"><?php esc_html_e( 'Oops! That page can&rsquo;t be found.', 'pressbooks-aldine' ); ?></h1>
				</header><!-- .page-header -->

				<div class="page-content">
					<p><?php esc_html_e( 'It looks like nothing was found at this location. Maybe try a search?', 'pressbooks-aldine' ); ?></p>

					<?php
						get_search_form();
					?>

					<div class="widget widget_categories">
						<h2 class="widget-title"><?php esc_html_e( 'Most Used Categories', 'pressbooks-aldine' ); ?></h2>
						<ul>
						<?php
							wp_list_categories( [
								'orderby'    => 'count',
								'order'      => 'DESC',
								'show_count' => 1,
								'title_li'   => '',
								'number'     => 10,
							] );
						?>
						</ul>
					</div><!-- .widget -->

				</div><!-- .page-content -->
			</section><!-- .error-404 -->

		</main><!-- #main -->
	</div><!-- #primary -->

<?php
get_footer();