Better looking 404 page

[ajcasagrande]

🚀 Feature Request

Right now the current 404 page is pretty bland:

For starters I think we could make it basic with just the headers and use the font and style of the current doc pages, so something like this, but with the font changed:

Maybe even throw in an Edgey for flair:

Edit: Apparently a better looking 404.html exists, but is not in use. It may also be missing the /lastest redirect logic, which would need to be added:

(Actual 404)

(404.html, if browsed directly to it)