Better looking 404 page

# 🚀 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)

Start by locating the existing 404.html and comparing it with the actual 404 page and current documentation styling. Verify how the /lastest redirect logic is handled, then confirm that the improved page is used for missing-page requests, matches the documentation font and style, and preserves the expected redirect behavior.

Written by the indexing model from the issue text.