themes-wordpress/reverie/patterns/404.php

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

?>

<!-- wp:group {"tagName":"main","style":{"spacing":{"blockGap":"var:preset|spacing|50","margin":{"top":"var:preset|spacing|80","bottom":"var:preset|spacing|60"},"padding":{"right":"var:preset|spacing|50","left":"var:preset|spacing|50"}}},"layout":{"type":"constrained"}} -->
<main class="wp-block-group" style="margin-top:var(--wp--preset--spacing--80);margin-bottom:var(--wp--preset--spacing--60);padding-right:var(--wp--preset--spacing--50);padding-left:var(--wp--preset--spacing--50)"><!-- wp:heading {"textAlign":"left","level":1,"fontSize":"x-large"} -->
<h1 class="wp-block-heading has-text-align-left has-x-large-font-size"><?php echo esc_html__( 'There\'s nothing here.', 'reverie' ); ?></h1>
<!-- /wp:heading -->

<!-- wp:paragraph -->
<p><?php echo esc_html__( 'The page you\'re looking for doesn\'t seem to exist.', 'reverie' ); ?></p>
<!-- /wp:paragraph -->

<!-- wp:spacer -->
<div style="height:100px" aria-hidden="true" class="wp-block-spacer"></div>
<!-- /wp:spacer --></main>
<!-- /wp:group -->