Initial commit. State 04.2021.

wp-content/themes/twentyfifteen/404.php

@@ -0,0 +1,30 @@
+<?php
+/**
+ * The template for displaying 404 pages (not found)
+ *
+ * @package WordPress
+ * @subpackage Twenty_Fifteen
+ * @since Twenty Fifteen 1.0
+ */
+
+get_header(); ?>
+
+	<div id="primary" class="content-area">
+		<main id="main" class="site-main" role="main">
+
+			<section class="error-404 not-found">
+				<header class="page-header">
+					<h1 class="page-title"><?php _e( 'Oops! That page can&rsquo;t be found.', 'twentyfifteen' ); ?></h1>
+				</header><!-- .page-header -->
+
+				<div class="page-content">
+					<p><?php _e( 'It looks like nothing was found at this location. Maybe try a search?', 'twentyfifteen' ); ?></p>
+
+					<?php get_search_form(); ?>
+				</div><!-- .page-content -->
+			</section><!-- .error-404 -->
+
+		</main><!-- .site-main -->
+	</div><!-- .content-area -->
+
+<?php get_footer(); ?>