RegionSection

Standard section surface treatment. Defaults to default when omitted. default uses the standard Base/theme section surface. alternate uses the standard visually distinct alternate surface while retaining normal section structure. transparent removes the standard section surface so the surrounding page or background shows through while retaining normal section structure. theme emits no standard appearance class and opts out of the complete standard Section surface recipe. The authored class and active theme own its background, foreground, internal padding, border, radius, shadow, and other surface behavior. Use it to replace the standard composition rather than merely recolor it. When the custom appearance creates a visible surface boundary, the theme must provide an appropriate internal inset; it may explicitly reuse the standard Section surface padding variables.

"default" | "alternate" | "transparent" | "theme"

Optional styling hook.

Stable document, section, or region identifier.

Maximum regions in each row.

minimum: 1 · integer only (no decimals)

Independently sized content regions.

Supporting text associated with the heading.

Semantic section heading.

Renders the section heading visually hidden but available to screen readers.

Identifies this as a standard content section.

"section"

Standard section width treatment. Defaults to default when omitted. default uses the standard constrained content width with normal outer breathing room. wide uses a wider constrained content width while retaining normal outer breathing room. full is a full-bleed treatment whose section surface extends edge-to-edge without an outer inline gutter or corner treatment by default; use it for backgrounds, imagery, media, and other continuous surfaces. Child content may remain independently constrained. theme applies no standard width treatment; the authored class and active theme own the width behavior.

"default" | "wide" | "full" | "theme"