First implementation

_pages/404.md

@@ -1,8 +1,9 @@
 ---
 title: "Page Not Found"
-excerpt: "Page not found. Your pixels are in another canvas."
+excerpt: "Page not found / ページが見つかりませんでした"
 sitemap: false
 permalink: /404.html
 ---
 
-Sorry, but the page you were trying to view does not exist.
+<br>
+ページが見つかりませんでした。