✅ SEP 25: Fix footer to bottom of viewport

Status: Finished 

Date: 2023-04-09 
Commit: 733b7e5f73a09e1835bae883d38bb00fd9c861a3 
> Used a simple CSS Flexbox on the body element with an auto-margin on the
> footer. Doesn't seem to have triggered any stylistic regressions, very happy
> with the result.

Currently (2023-04-09) the HTML footer floats below the document <main>. This is fine, but I would prefer that, where a document does not occupy the full height of the viewport, the footer sit at the bottom of the viewport.

Beyond pure aesthetics, in site sections that make use of footer navigation links (proposals, nonsense, et al), and tend toward shorter documents (particularly nonsense) this would allow for quickly navigating through the chronology using said footer links without having to move the mouse.