/** Parse `"14px"` / `"14"` / `14` → number; invalid → fallback. */
export declare function parseCssPx(value: unknown, fallback: number): number;
/** Normalize a size to a CSS length token (`14` → `"14px"`). */
export declare function toCssPxToken(value: unknown): string | undefined;
/** Relative luminance 0–1 (simple Rec.601); null if unparsable. */
export declare function relativeLuminance(color: string): number | null;
/**
 * Keep dark analytics / diagram chrome when UI pack surfaces are light.
 * Prevents white gauges / washed node fills from light presets.
 */
export declare function pickChrome(uiColor: string | undefined, fallback: string): string;
/** Ink that contrasts against a background. */
export declare function contrastingInk(bg: string, light?: string, dark?: string): string;
export type FontSizeTriple = {
    fontSize: number;
    fontSizeSm: number;
    fontSizeLg: number;
};
/** Resolve base/sm/lg from token strings; derive sm/lg when only base is set. */
export declare function resolveFontSizeTriple(tokens: {
    fontSize?: string;
    fontSizeSm?: string;
    fontSizeLg?: string;
}, fallbacks: FontSizeTriple): FontSizeTriple;