# Accessibility

## Accessibility checks

- Markdown image or `::image` without alternative text;
- `image-*` layout without `image=`;
- empty heading, skipped heading level (h1 → h3);
- Mermaid diagram without `title="…"` (the title becomes the accessible name of the SVG).

## Syntax diagnostics

Invalid front matter or front matter that looks like a slide, unknown layout or transition,
malformed slide JSON, duplicated slide id. Every diagnostic points to a line of the source file.