{{-- Shared print / PDF CSS. Dompdf-compatible only: - No JavaScript, no external resources. - Layout is tables + fixed widths in mm/pt (Dompdf is unreliable with flexbox and modern CSS). - Every user-visible section — header, hero, info, items, totals, payments, footer — is anchored to `--doc-width` (186mm on Letter) so the left and right borders align vertically all the way down. --}}