themes-wordpress/nested/patterns/404.php

<?php
/**
 * Title: A 404 page
 * Slug: nested/404
 * Inserter: no
 */

?>

<!-- wp:heading {"textAlign":"left","level":1,"anchor":"oops-that-page-can-t-be-found"} -->
<h1 class="wp-block-heading has-text-align-left" id="oops-that-page-can-t-be-found"><?php echo esc_html__( 'Oops! That page can’t be found.', 'nested' ); ?></h1>
<!-- /wp:heading -->

<!-- wp:paragraph {"style":{"typography":{"fontSize":"1.5rem"}}} -->
<p style="font-size:1.5rem"><?php echo esc_html__( 'It looks like nothing was found at this location. Maybe try a search?', 'nested' ); ?></p>
<!-- /wp:paragraph -->