Build a theme from a partial over a base preset (default: light).
Validates key WCAG pairs and WARNS (never blocks) when a pair falls
below its threshold: brand themes start from a checked baseline
instead of a copied preset. Thresholds: body text 4.5:1 (AA),
secondary text 4.5:1, muted text and accent-as-UI 3:1 (AA
non-text/large).
Build a theme from a partial over a base preset (default: light). Validates key WCAG pairs and WARNS (never blocks) when a pair falls below its threshold: brand themes start from a checked baseline instead of a copied preset. Thresholds: body text 4.5:1 (AA), secondary text 4.5:1, muted text and accent-as-UI 3:1 (AA non-text/large).