404.php in WordPress Themes — a practical guide to WordPress 404.php with clear examples you can reuse in real projects.
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Short description
A good 404 page reduces bounce rate — include search form and navigation back to key pages.
404 sketch
<?php get_header(); ?>
<h1><?php esc_html_e('Page not found', 'acme-theme'); ?></h1>
<?php get_search_form(); ?>
<?php get_footer(); ?>