Make a custom 404 page for Blogger

Several days ago ,Blogger team announced new SEO functions for Blogger after a long time waiting :D These functions are grouped in Meta Tags, Errors and Redirections, and Crawlers and Indexing.In Redirections group,we got 404 page function and redirect dead links .Now in this post ,I will show you how to create a custom 404 page for all Blogger templates and Simplex's templates .Demo here