URLs in links to pages on the same server
When you're linking to another page on the same server, use a
site-root-relative URL starting with /, even if you're linking to a
page in the same directory as the page you're linking from.
Note: There are many valid linking styles; this guideline isn't a general statement about best practices for linking in all contexts, it's just our house style.
Use "https" when possible
When you're linking to a page on another server (and therefore using an
absolute URL), and the server you're linking to supports HTTPS, start the URL
with https rather than http. If the server doesn't
support HTTPS, then start the URL with http.