[JGalego]

Two problems the landing page's own invitation created: it sends people to
a playground that did not work on a phone, and it made everybody download
an SVG renderer to get there.

The playground on a phone

The inspector holds a fixed 290px beside a card up to 640 wide, so on a
375px screen the card was pushed off the left edge and the whole page
scrolled sideways.

Below 60rem the columns become rows, the card scales to the room it has, and
the inspector becomes a sheet the View menu opens rather than a column
that is always there. 60rem, because 640 + 290 cannot fit under about 960 —
landscape phones very much included.

The rules live in apps/web/src/mobile.css, layered over the theme rather
than folded into it: the theme belongs to the desktop, where the window is
never 375 pixels wide. The zoom comes from measuring the stage with a
ResizeObserver, not the window, because the menu bar, the status bar and
any open sheet have taken their share first — and a landscape phone has
plenty of width and almost no height.

Three attempts got this wrong before measurement caught them: a 48rem
breakpoint that let landscape phones fall through to the desktop layout; a
ResizeObserver that never attached, because App returns early with a
loading notice and the ref was still null when the effect ran; and a
sideways-scrolling menu bar, where overflow-x made a clipping context and
cut off the menu dropping out of its own button. The bar wraps now.

One shared file

Part.tsx divides a drag by the scale it measures off the part, so a part
lands where the finger left it on a scaled card. At 1:1 the divisor is one
and the desktop is unchanged — checked by driving both (zoom 0.95 → 42 card px, expected 42; zoom 1.00 → 40, expected 40). It also rounds to
whole pixels now, which it should always have done.

The exporters are fetched when somebody exports

An SVG renderer, a font database and a text shaper come with PDF and Decker
export, and together they were most of what HyperLab compiled to.

	before	after
runtime wasm, every visit	1.62 MB gzip	326 KB gzip
exporters	in the bundle	1.62 MB gzip, first export only

They are now crates/web-export, a module of its own. The seam is the
stack's own single-file JSON, so the two modules share no state. That needed
a stack_text command distinct from save_stack_json — the latter marks the
document clean, because a download is the save, and exporting a PDF is not
saving.

Verified

CI green on 3306348. Beyond that, the built site was driven in Chromium:

• Portrait, landscape and the 640px Cluedo card all sit inside the viewport
  with no sideways scroll; the desktop keeps its inspector, its unscaled
  card and no View menu.
• Opening Cluedo fetches the runtime and neither the exporters nor the
  typeface. Exporting fetches both, once. The PDF still carries its artwork
  labels.

🤖 Generated with Claude Code

https://claude.ai/code/session_01R7eaxUAqy2gKQSBNnYZoFr

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Generated by Claude Code