/**
 * WCAG Token Checker — WA-401
 * Post-pull audit utility that checks design tokens against WCAG contrast
 * and spacing criteria. Self-contained: no external color libraries required.
 */
import type { DesignSystem } from "../engine/registry.js";
export interface TokenWcagResult {
    tokenName: string;
    type: "color" | "spacing" | "other";
    issue: string | null;
    wcagCriterion: string | null;
    status: "pass" | "warn" | "fail";
}
export interface WcagTokenReport {
    results: TokenWcagResult[];
    summary: {
        pass: number;
        warn: number;
        fail: number;
        total: number;
    };
    hasFailures: boolean;
}
/**
 * WCAG relative luminance for an RGB triplet (each 0-255).
 */
export declare function relativeLuminance(r: number, g: number, b: number): number;
/**
 * WCAG contrast ratio between two relative luminance values.
 * Returns value in [1, 21].
 */
export declare function contrastRatio(l1: number, l2: number): number;
/**
 * Parse a hex color string (#rgb, #rrggbb, #rrggbbaa) into {r,g,b} (0-255).
 * Returns null if the string is not a valid hex color.
 */
export declare function parseHex(hex: string): {
    r: number;
    g: number;
    b: number;
} | null;
/**
 * Compute the maximum contrast ratio between a hex color and
 * pure white (#fff, luminance ~1) and pure black (#000, luminance 0).
 * Returns null when hex is not parseable.
 */
export declare function maxContrastAgainstExtremes(hex: string): number | null;
/**
 * Audit design tokens for WCAG violations.
 *
 * - Color tokens (name contains color/fg/bg/text/fill/surface/brand):
 *   checks hex values against white and black for contrast compliance.
 *   fail  < 3.0:1   — inaccessible for any text use
 *   warn  3.0–4.49  — AA-large only
 *   pass  ≥ 4.5     — meets WCAG 1.4.3 AA
 *
 * - Spacing tokens: warns on values < 24px (WCAG 2.5.8).
 *
 * - All other tokens: pass (no applicable WCAG check).
 */
export declare function auditTokensForWcag(tokens: DesignSystem["tokens"]): WcagTokenReport;