Page · stable · v1.0.0 · owner: Site system lead · contract 19 of 20 points (open: figma)
Do and don't
Do: Section map and native recovery actions
Declared by not-found.tsAuthored page specimen; not a captured route or acceptance result. Open associated page (declared association; rendered-page verification is separate).
Open example: Not found · Do: Section map and native recovery actions Use the full-page example to follow page links.
Do: Different recovery explanation and destinations
Declared by not-found.tsAuthored page specimen; not a captured route or acceptance result.
Open example: Not found · Do: Different recovery explanation and destinations Use the full-page example to follow page links.
Don't: Missing recovery destinations
Declared by not-found.tsAuthored page specimen; not a captured route or acceptance result.
Refused by the element. page-404: page-404.sequence: page-head does not follow page-404 (page-head → tile-grid).
Don't: Two missing-page fields touching
Declared by not-found.tsAuthored page specimen; not a captured route or acceptance result.
Refused by the element. page-404: D-SITE-002: compose page-404: a madder field touches a madder field (D-SITE-002: a field is always followed by cotton)
Rules
| Rule | Why | Check |
|---|---|---|
| Built pages follow: header, page-head, tile-grid, footer. | A declared composition is what makes the page checkable and the site consistent. | Automated: scripts/site/system/check-pages.ts (check_composition per page) |
API
No props.
Contract details
The full contract: identity, anatomy, variants, states, tokens, layout, motion, accessibility, content, tests
Identity
| Aspect | Value |
|---|---|
| Id | page-404 |
| Layer | Pages |
| Category | page |
| Owner | Site system lead |
| Status | stable |
| Version | 1.0.0 |
| Source | apps/showcase/site/system/pages/not-found.ts (private repository; the contract and the render function are this one module) |
| Version | Date | Change |
|---|---|---|
| 1.0.0 | 2026-10-26 | Not found as one module: its markup moved out of the page builder (scripts/site) into the system. |
Use when
- Paths matching /^\/404\.html$/. Why: Every page of this kind is composed the same way, so readers learn it once.
Do not use when
- For a page with a different job. Why: A new kind of page gets its own declaration and review.
Anatomy
| Part | What it is |
|---|---|
| 1 | page-head |
| 2 | tile-grid |
Made of: header, page-head, tile-grid, footer.
Used in: pages directly.
Variants
| Variant | When | Why |
|---|---|---|
| default | Wherever the page declaration places it. | One shape per job keeps pages predictable. |
States
| State | Rendered or not applicable |
|---|---|
| default | default |
| hover | Not applicable: The not found is not interactive, so it has no hover state. |
| focus-visible | Not applicable: The not found does not take focus; links and buttons inside it carry their own focus ring. |
| active | Not applicable: The not found cannot be pressed. |
| disabled | Not applicable: The not found has nothing to disable. |
| loading | Not applicable: The not found is rendered at build time and is complete when the page loads. |
| empty | Not applicable: The not found is not rendered without content; the builder skips it. |
| error | Not applicable: The not found shows no data that can fail. |
| current | Not applicable: The not found has no current item. |
| visited | Not applicable: The not found is not a link. |
| expanded | Not applicable: The not found does not open or close. |
Tokens
| Part | Token |
|---|---|
| page.ground | --cotton |
Layout
| Aspect | Value |
|---|---|
| breakpoints | Required review at 390, 768, 1024 and 1440 px; execution is not implied by this declaration; columns stack under 768 px; the wrap keeps a 16 px gutter on phones. |
| wrapping | Text wraps; nothing scrolls sideways. |
| textExpansion | Japanese runs 20 to 40% longer; headings break between phrases (jaBreaks) and blocks grow downwards. |
Spacing and rhythm
| Aspect | Value |
|---|---|
| internal | Each template's own padding. |
| external | None. |
| rhythm | Field, cotton, field: never two fields touching; the woven edge at each join (D-SITE-002, D-SITE-003). |
Motion
| Aspect | Value |
|---|---|
| None | No intrinsic element animation. The optional claude-entrance consumer profile may translate below-fold structure once (20px, --dur-weave, --ease-enter, --stagger); reduced motion disables it. This preserved baseline entrance is separate from element playback. |
Runtime and reuse
Render-only element; mount any registered child enhancements separately. Preserve required Site CSS, fonts, responsive and locale rules from nativeElement.
Accessibility passport
| Aspect | Value |
|---|---|
| role | a landmark or list, as stated in its parts |
| name | Its visible text |
| keyboard | Links and buttons inside, in reading order. |
| focus | The --focus ring on every link and button inside. |
| screenReader | Read in source order; decorative weaving is aria-hidden. |
| contrast | Ink on cotton 14:1; text on every dye field 4.5:1 or better (checked by check-brand). |
| target | Links and buttons are 44 px tall. |
Content
| Slot | Length | Voice |
|---|---|---|
| page-head: missing-page message | One clear missing-page title and brief recovery explanation; use the native madder state override. | State the problem plainly without blame or a false success message. |
| tile-grid.tiles: recovery destinations | Real section links in the registered tile grid; no article body or additional action field in this page kind. | Name destinations so the reader can continue from the site map. |
Good: “This page has come loose. Choose a section below to find your way back.”
Bad: “Everything worked! — on a missing-page response.” · “Try again later — with no recovery destination.”
Japanese: The native 404 document is English and has no declared Japanese counterpart. Do not manufacture a Japanese route; a future translation must preserve the missing-page meaning and real recovery links.
Icons and illustrations
None: this element uses no icon or illustration of its own.
Decisions and exceptions
- D-SITE-002: A field is always followed by cotton; two fields never touch
- D-SITE-003: The woven edge sits at every field/cotton join, and nowhere else
Usage
1 uses across the built pages (measured by npm run site:system).
Tests
| Aspect | Value |
|---|---|
| unit | tests/unit/site-system.test.ts: renders every do and don't example through the registry and checks the classes it owns |
| visual | Not yet: there are no screenshot baselines; the Library page is checked for sideways scroll at 1440 px by tests/site/system.spec.ts |
| a11y | tests/site/system.spec.ts: axe (0 serious or critical) on the element's Library page in light and dark |
| parity | scripts/site/system/check.ts: Library examples are rendered by the same render function the site imports |
Figma
not-yet: The Loom Site Figma library is the last stage of the plan; this element is not mapped yet.