/** Accessibility helpers — contrast, high-contrast palette. */
/** Contrast ratio between two CSS colors (1–21). */
export declare function contrastRatio(fg: string, bg: string): number;
/** WCAG AA normal text: ratio ≥ 4.5. */
export declare function meetsWcagAA(fg: string, bg: string): boolean;
declare const HC_PALETTE: {
    bg: string;
    fg: string;
    accent: string;
    border: string;
    muted: string;
};
/** Map a color to high-contrast palette when enabled. */
export declare function toHighContrastColor(color: string | null | undefined, kind?: 'fill' | 'stroke' | 'text'): string;
export { HC_PALETTE };