CngxAccordionSkin

Description#

Selectable visual skin for <cngx-accordion-group>.
The skin is a pure thematic concern - every value renders the identical heading / region / marker structure, slots, ARIA, and keyboard behaviour, and only redirects CSS via the [data-skin] host attribute. Typed class-sugar (mirrors CngxTabsSkin), not a behaviour-branching mode flag.

'editorial' mono index + hairlines; 'categorized' bordered surface cards; 'plus-minus' one framed surface with a boxed +/- marker; 'lux' generous whitespace, large type; 'bento' container-query card grid; 'section-bands' inverted full-width header bands; 'timeline' a rail with per-item nodes; 'severity-spine' a full-height priority spine; 'primary-frame' a solid primary border + glow on open.