Slide options

Front matter

Key	Example	Effect
`title`	`Lorem ipsum`	deck title (footer `{title}`, browser tab, galleries)
`author`	`Dolor Sit`	footer `{author}`
`description`	`"…"`	galleries and HTML description
`aspectRatio`	`16:9`, `4:3`	design size 1280×720 or 1024×768
`theme`	`light`, `dark`, `system` or an object	default mode or theme overrides
`lang`	`en`, `fr`	interface language (controls, presenter console, remote)
`footer`	`false` or an object	disables or overrides the footer
`rules`	object	density limits for this deck

Option	Values	Effect
`layout`	`default`, `center`, `cover`, `section`, `grid`, `columns`, `split`, `image`, `image-left`, `image-right`	see Layouts
`cols`	`1` – `4`	grid columns
`ratio`	`1:1`, `2:1`…	column proportions
`image`, `alt`, `fit`	path, text, `cover` / `contain`	image layouts
`overlay`	`0` – `1`	darkening of the background image
`transition`	`slide`, `fade`, `none`	transition to this slide
`bg`	CSS color	slide background
`footer`	`true`, `false`	forces or hides the footer
`id`, `title`	text	identifier, title in search results

Unknown values produce a diagnostic with the line number.