Molecule · stable · v1.0.0 · owner: Site system lead · contract 19 of 20 points (open: figma)
Do and don't
Do: A product page
Rendered by breadcrumbs.tsOpen example: Breadcrumbs · Do: A product page Use the full-page example to follow page links.
Do: Japanese
Rendered by breadcrumbs.tsOpen example: Breadcrumbs · Do: Japanese Use the full-page example to follow page links.
Don't: The current page as a link
Rendered by breadcrumbs.tsOpen example: Breadcrumbs · Don't: The current page as a link Use the full-page example to follow page links.
Don't: On the landing
Rendered by breadcrumbs.tsOpen example: Breadcrumbs · Don't: On the landing Use the full-page example to follow page links.
Rules
| Rule | Why | Check |
|---|---|---|
| The current page is the last item and is not a link. | A link to the same page wastes a tab stop. | Automated: tests/unit/site-system.test.ts |
API
| Prop | Type | Required | Default | What it does |
|---|---|---|---|---|
items | list | Yes | From home to the current page; the last has no href. | |
lang | en | ja | No | "en" | Labels the nav in the page's language. |
Contract details
The full contract: identity, anatomy, variants, states, tokens, layout, motion, accessibility, content, tests
Identity
| Aspect | Value |
|---|---|
| Id | breadcrumbs |
| Layer | Molecules |
| Category | navigation |
| Owner | Site system lead |
| Status | stable |
| Version | 1.0.0 |
| Source | apps/showcase/site/system/molecules/breadcrumbs.ts (private repository; the contract and the render function are this one module) |
| Version | Date | Change |
|---|---|---|
| 1.0.0 | 2026-10-26 | The path back from a deep page, above its title. |
Use when
- Every deep page, above the h1. Why: Most readers arrive on deep pages from search, not from home.
Do not use when
- On the landing or a task page. Why: There is no path above them.
- As the only navigation. Why: Breadcrumbs go up, not across.
Anatomy
| Part | What it is |
|---|---|
| root | nav.crumbs labelled Breadcrumb |
| list | ol of links |
| current | The last item, aria-current=page, not a link. |
Made of: text-link, tokens:type.
Used in: page-head.
Variants
| Variant | When | Why |
|---|---|---|
| path | Deep pages. | One form everywhere. |
States
| State | Rendered or not applicable |
|---|---|
| default | Links in --ink-2 |
| hover | Underline in full colour. |
| focus-visible | The --focus ring. |
| active | Not applicable: Navigation is instant. |
| disabled | Not applicable: Every level above exists. |
| loading | Not applicable: Static. |
| empty | Not applicable: Not rendered on pages without a path. |
| error | Not applicable: Links are checked at build. |
| current | The last item, aria-current=page, in ink. |
| visited | Not applicable: Same colour: it is a path, not a reading list. |
| expanded | Not applicable: Does not open. |
Tokens
| Part | Token |
|---|---|
| root.font | --type-small-strong |
| link.color | --ink-2 |
| current.color | --ink |
| separator | a dot in --ink-2 |
| --breadcrumbs-gap-space-3 | var(--space-3) |
| --breadcrumbs-gap-space-5 | var(--space-5) |
| --breadcrumbs-margin-space-9 | var(--space-9) |
| --breadcrumbs-font-type-small-strong | var(--type-small-strong) |
| --breadcrumbs-border-radius-radius-round | var(--radius-round) |
| --breadcrumbs-color-ink-2 | var(--ink-2) |
| --breadcrumbs-color-ink | var(--ink) |
Layout
| Aspect | Value |
|---|---|
| breakpoints | Required review at 390, 768, 1024 and 1440 px; execution is not implied by this declaration; wraps on phones. |
| wrapping | Wraps between items. |
| textExpansion | Japanese labels wrap between items. |
Spacing and rhythm
| Aspect | Value |
|---|---|
| internal | --space-4 between items. |
| external | --space-6 above the h1. |
| rhythm | Part of the page head. |
Motion
| Aspect | Value |
|---|---|
| None | Static. |
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 | navigation (Breadcrumb / パンくずリスト) |
| name | Breadcrumb |
| keyboard | Tab through the links. |
| focus | Before the page's h1. |
| screenReader | Announces the navigation, the list and the current page. |
| contrast | --ink-2 on cotton 8.6:1. |
| target | Inline links, 24 px line box. |
Content
| Slot | Length | Voice |
|---|---|---|
| label | 3 words | The page's short name |
Good: “Home · Product · Operations”
Bad: “Home > Pages > Product page”
Japanese: Labels come from nav-ja.ts; English-only pages are marked （英語）.
Icons and illustrations
None: this element uses no icon or illustration of its own.
Decisions and exceptions
Usage
65 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.