# Mermaid

> Renders a Mermaid diagram with a concise accessible name, prose summary, and visible structured text alternative.

- Status: alpha
- Group: media
- Page: https://www.digitaltableteur.com/design-system/components/mermaid
- Contract: https://www.digitaltableteur.com/contracts/v1/Mermaid.contract.json

## When to use

Renders a Mermaid diagram with a concise accessible name, prose summary, and visible structured text alternative.

## When not to use

- Do not render a diagram without a complete accessibleDetails equivalent.
- Do not use title alone as the text alternative for a diagram with meaningful relationships.

## Look-alikes

The contract names no look-alike with a deciding condition.

## Props

| Prop | Type | Default | Description | Required |
| --- | --- | --- | --- | --- |
| `chart` | `string` | none | Mermaid diagram source. | Yes |
| `title` | `string` | none | Concise meaningful name for the diagram. | Yes |
| `description` | `string` | none | Short prose summary of the diagram purpose and relationships. | Yes |
| `accessibleDetails` | `ReactNode` | none | Structured or prose equivalent of every material relationship in the diagram. | Yes |
| `detailsLabel` | `string` | none | Label for the visible text-alternative disclosure. | No |
| `caption` | `string` | none | Optional visible figure caption. | No |
| `className` | `string` | none | Additional className for the figure. | No |
| `themeColors` | `MermaidThemeColors` | none | Diagram color overrides: CSS colours or var(--token) references. Defaults to --color-text and --color-border, so diagrams follow the theme. | No |

## Variants

No variant dimensions and no props with a fixed set of values.

## Invalid combinations

The contract records no invalid combinations.

## Keyboard

| Key | Behaviour |
| --- | --- |
| Tab | Focuses the native disclosure summary. |
| Enter or Space | Toggles the text alternative. |

## Rules

Every item under When not to use is a MUST NOT. MUST and SHOULD follow RFC 2119.

| Level | Rule | How it is checked |
| --- | --- | --- |
| MUST | ARIA: The rendered diagram has role img and is named by title. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: Description supplies a concise accessible description. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: Aria-details points to a visible disclosure containing a complete structured or prose equivalent of the diagram relationships. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | ARIA: The generated SVG is hidden from assistive technology to prevent duplicate, unstructured narration. | Not yet verified: no evidence record. WCAG 4.1.2. |
| MUST | Required stories produce no axe violations at the configured severity. | Automated by `npm run test:stories:matrix:ci`. WCAG 2.5.8. |
| MUST | The accessibility tree (role, name, state) matches the committed snapshot for every required story. | Automated by `npm run test:stories:matrix:ci`. WCAG 1.3.1, 4.1.2. |
| MUST | The component remains legible and operable under a real browser forced-colors: active pass. | Automated by `npm run test:stories:hc`. |
| MUST | Every documented keyboard interaction works as specified. | Not yet verified: no evidence record. WCAG 2.1.1, 2.1.2. |

## Install and import

- In-repo only. Mermaid is not exported from `@digitaltableteur/react`, so there is no public import path.
- Alpha components are internal and never exported.

## Links

- Machine-readable contract (Design System Contract 1.0): https://www.digitaltableteur.com/contracts/v1/Mermaid.contract.json
- Markdown version of this page: https://www.digitaltableteur.com/design-system/components/mermaid.md
- Component index as JSON: https://www.digitaltableteur.com/design-system/components.json
- All components: https://www.digitaltableteur.com/design-system/components
- Source: The implementation lives in a private repository. This page, its Markdown twin and the contract are generated from it at build time and are the public source of truth.