Design/Link colors

Examples
[actual links. Using the same order as the table above]
 * unvisited (don't click!)
 * local: Category:Extensions/de-formal
 * interwiki: foobarbang
 * external: https://www.example.org/123
 * visited (click these, if they're not purple)
 * local: MediaWiki
 * interwiki: MediaWiki
 * external: https://www.mediawiki.org/
 * missing
 * unvisited: foobarbazqux (don't click!)
 * visited: foobarbaz (click this)