#What the output is

A pamphlet is one HTML file containing five things: a shell, styles, body HTML, inlined diagram SVG, and a small runtime script. Plus an HTML comment holding the source file verbatim.

pamphlet build --verbose shows what each weighs.

#It asks the network for nothing

No <link>, no <script src>, no CDN reference, no remote font.

The compiler enforces this: referencing a remote image fails the build (EMB-403), with no escape hatch.

#Complete with JavaScript off

Not a word is lost. This is the starting point rather than a patch: every interaction must have a script-free form first, and scripting is layered on top.

#Dark by default, light only when printed

The output is always dark and does not consult the reader's system setting: it is one file sent to someone, so it should look like one thing rather than two depending on whose machine it lands on.

The light variable set is in the output too, but only takes effect under @media print — a dark background prints as a full page of ink, and most print settings drop backgrounds, which would leave light text on white paper: a blank page. Both sets are pure CSS, not a line of JavaScript involved.

Diagram colours are in the same layer, so lines and text inside diagrams change with it. Hard-coded colours in engine output that could not be substituted report DIAG-304 at compile time.

#Narrow screens scroll, they do not reflow

Pamphlet does not do responsive layout. Body text is capped at 52rem and centred; on narrow screens tables and code blocks scroll horizontally rather than being squeezed into wrapping.

That is deliberate: reflowing destroys the readability of tables and diagrams, while horizontal scrolling at least preserves the shape of the content.

#Opening it on a phone

Pamphlet does not promise how you get the output open on a phone; it promises the experience once it is open.

The second half holds completely: opened in a mobile browser (from a local file or a URL), tabs click, diagrams are sharp, and it follows the system colour scheme.

The first half is not something Pamphlet can fix:

• Since iOS 18.5, Safari no longer opens local HTML files directly (https://discussions.apple.com/thread/256102223, reproduced by several people on Apple's community forum; that is a community thread, not official documentation)
• WeChat's built-in browser blocks local HTML from executing by default (Chinese technical community sources, not official documentation)

Together, "send the HTML over chat and they tap it open" is unlikely to work on iOS in 2026.

#Three ways around it

:::steps

1. On iOS, open it via the Files app. Save it there, long-press → open in Safari. That path does work.
2. Have the sender put it on any web server. The output is a single static file; GitHub Pages, object storage, or any nginx on a company network will serve it with no server-side cooperation.
3. Send a PDF instead. Open the output on a computer and print to PDF. Interactivity is lost but the whole content is readable — because the no-JavaScript fallback already requires everything to be visible when expanded. :::

#Why there is no "mobile version"

--format hosted (an extra hostable multi-file build for mobile) was considered and rejected:

• It contradicts the "self-contained single file" identity
• It means maintaining a second assembly path and a second test suite
• And it would still hit the same wall — what iOS blocks is local files, and a multi-file build is still local files

Any scheme that tries to get around this limit adds complexity to the output and stays limited anyway.

Narrowed, the promise holds completely: CSP, location.hash deep links, data URI fonts and the light print styles were all verified under file://. Leaving an undeliverable promise standing does more damage than narrowing it.

Source: ADR-0018

#The output is its own backup

The source is stored verbatim in an HTML comment by default, and pamphlet extract gives it back. Even with nothing but the HTML file, the original is not lost.

--no-embed-source turns that off, at the cost of the recovery.