Bug fix — final-page white area:

Cause: body box paints the page but is only as tall as its content. Last-page tail below the content = bare page canvas, which Firefox won't print unless you tick "Print backgrounds." Short final page = mostly white.

Fix: a position:fixed paper layer (body::before) in @media print. Fixed elements are honored by print-color-adjust, and Firefox repeats them full-height on every page — so paper now covers every sheet including the tail, no checkbox needed. Also dropped the "tick Print backgrounds" hint from the print view and updated README.