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Production

What the Browser Already Sets

·7 min in full, in the book·PagePerfect Journal

Eleven lines of CSS and a headless Chrome produced a five-page PDF whose sheets measure 432 by 648 pt, the 6 by 9 inches the file asked for, with a wide inner margin that swaps sides on every page.12 The February draft said a browser could do none of that. The list of what is genuinely missing is shorter than that, and it varies from one browser to the next.

The rest of this essay is in the book

It goes on to cover:

  • What the test printed
  • No engine has the whole set
  • The layer that reaches the printer
  • The cross-reference nobody has shipped
  • Line breaking, and what changed under it
  • What TeX does and does not do
  • The part no engine decides
  • What to send the file through

About the book

Notes

  1. Own test, 2026: Chrome and @page, research/R4b/chrome/t.html, out.pdf; MDN browser-compat-data n.d., size (chrome 15, firefox 95, safari 18.2); page-orientation (chrome 85, firefox 122). Printed with Chrome 152.0.7977.85 in headless mode on 16 September 2026. pdfinfo reported five pages at 432 by 648 pt, which is the 6 by 9 in requested by the @page rule, and pdftotext found the margin-box text on the pages it belonged to. Evidence A: strong or direct evidence.
  2. Own test, 2026: Chrome verso and recto margins, research/R4b/chrome/t.html, out.pdf; per-page glyph extents from pdftotext -bbox. The same five-page test, with @page :left and @page :right carrying a 40 mm inner and 10 mm outer margin. Odd pages measured 119.2–404.2 pt, even pages 28.3–310.4 pt. One browser on one operating system; nothing here is a claim about Firefox or Safari. Evidence A: strong or direct evidence.

Sources

  • Own test: Chrome print-to-PDF honours @page size, margins and margin boxes, 2026-09-16.
  • MDN browser-compat-data. css/at-rules/page.json (main branch). raw.githubusercontent.com
  • Own test: Chrome print-to-PDF honours @page :left and :right margins, 2026-09-16.

Further reading