Print and export

What we guarantee

Printing is treated here as an accessibility surface rather than a convenience, for two reasons that are specific to this domain. Compliance reviewers read documentation on paper and annotate it. And patients print or screenshot results to take to an appointment, which means a printed health value becomes a clinical artefact in somebody else's hands, stripped of every tooltip and hover state that explained it.

app/globals.css carries a real @media print block. It does the following, and each item is there because of a specific failure:

• Removes chrome that carries no information on paper, so the printed page starts with the content. The banner, the main navigation, the sidebar, the sub-navigation and the table of contents are each named individually. It never removes aside as an element, and it says so in a comment: <StubNotice>, <SafetyCallout> and <ResearchNote> are all asides, and the same block restores those three positively so that a later chrome selector cannot quietly take them out again. A caveat that vanishes on paper is worse than no caveat, because the reader cannot tell it was ever there.
• Forces a white background and black text at 11pt, because a dark-theme print is unreadable and wastes toner.
• Strips backdrop-filter, box-shadow and text-shadow globally. Translucency does not survive a printer; it prints as a grey smear over the text.
• Puts a 1pt solid black border around every [data-status] element and sets print-color-adjust: exact. The status word is always present, so the colour is not load-bearing. Even so, the border means the pill is still visibly a discrete object after a black-and-white photocopy.
• Resolves external link targets into the text, appending the URL after any http link inside main. A printed page with a bare "see here" is useless in a review file.
• Prevents tables, figures, code blocks, block quotes and safety callouts from splitting across a page break, and keeps headings with the content that follows them. A threshold table broken across two sheets is a classic way for a reviewer to misread a number.
• Sets an 18 mm page margin, so there is room to write in.

The product theme adds a second @media print block of its own in app/product.css. It redeclares --background, --card, --foreground, --card-foreground, --muted-foreground and --border as ink on paper, and it carries every material rung to its opaque fallback. So a screen printed from the dark theme prints as ink on white rather than as pale text on a dark fill. This is the half a consuming product actually ships, because the product stylesheet travels with the theme a product installs while the docs-site globals.css above does not.

What you own

What a printed result must still say. This is the important half of the page. A health value on paper has lost its context and gained an unknown reader. It must still carry:

1. The value, its unit and its precision. They are never truncated and never abbreviated past recognition.
2. When it was measured, as an absolute date and time. RelativeTime renders "2 hours ago" on screen, which is meaningless on a sheet of paper found next week. Anything printed resolves to an absolute stamp.
3. What measured it, where that affects how the number should be read. See Data provenance and device accuracy.
4. The status word, not the status colour.
5. The disclaimer, if one was shown on screen. A printout that drops the "this is not a diagnosis" line has changed what the document claims.
6. A visible boundary. The print stylesheet drops a background colour and a box-shadow, and it keeps an outline and a border. A surface that leaned on its fill or its shadow to show where it ends prints as boundaryless content on a same-coloured page. opsinjs draws a Surface edge as an outline for exactly this reason, so a surface at a rung that publishes a border keeps its boundary on paper. That is the card, raised, sheet and overlay rungs, which is what Card, MetricTile, Dialog and Sheet render. The three rungs that publish no border by design, canvas, inset and scrim, draw no edge on screen or on paper, so a panel built on one of those prints boundaryless, and a product that draws its own container edge must reach for a property in the second group, an outline or a real border, never the first.

Pagination of long data. A twelve-month log printed as one enormous table needs repeated headers on each page. That is a product decision.

Whether printing is offered at all. Some data should not be trivially exported. See On-screen privacy.

How to check

Measured results

There is no automated print check. A rendered-to-PDF snapshot of the reviewer path would be the right artefact, and it needs a browser automation pass that this project deliberately does not install.

Known gaps

• The print stylesheet has never been tested against a real printer, only reasoned about.
• There is no PDF export path, for the reviewer bundle or for anything else; printing is the only route to paper.
• The printed-value rules are implemented per component, but nothing verifies a whole screen end to end. RelativeTime resolves to an absolute stamp in print (print:not-sr-only), Surface draws a printed boundary on every rung that publishes a border, and several components ship print: rules, so the rules are no longer absent. What is still missing is any check that one screen carries the value with its unit and precision, the status word and the disclaimer onto paper together, because there is no automated print capture to assert against.
• Page numbers, running headers and a printed provenance footer are not implemented, beyond the review stamp the stylesheet appends to [data-reviewed].

Updates to this page

Last read through against the system on 2026-09-02. Due for review every 12 months; expiry is reported by pnpm run check:freshness.