Deterministic pagination: multi-page document preview should match PDF export

What problem are you trying to solve?

Open Design can't produce real multi-page documents that behave like a word processor. For multi-page, multi-column body text, the HTML preview doesn't match the exported PDF — different page count and column/line breaks. You can tweak the layout in HTML but can't trust the PDF to match. That blocks letters, reports and grant documents.

Cause: preview (@media screen, fluid scroll) and PDF export (@media print, fixed pages) are different render paths, and CSS doesn't paginate multi-column flow across pages reliably.

Describe the solution you'd like

A generic text-flow capability like linked text frames in a word processor: content flows automatically and consistently across pages, no matter how much is entered. One engine renders preview AND export identically, so preview == PDF by construction.

Alternatives you've considered

Native CSS multi-column (unreliable across pages), Paged.js (buggy for columns), Vivliostyle (preview == PDF by design, but AGPL-3.0), or a custom pre-pagination engine. Deck export already works by shipping fixed pages — a good template.

Would you be willing to contribute a PR?

Yes, with guidance from a maintainer