import type { CssVarDecl } from "./css-vars.js";
/** Any supported CSS color form to lowercase 6-digit hex; null when not one.
 *  A trailing `!important` is declaration noise, not color — stripped. */
export declare function normalizeColor(value: string): string | null;
/**
 * Resolve `var(--x)` / `var(--x, fallback)` references against the collected
 * declarations (bounded depth). Returns null when a reference cannot be
 * resolved — theme.json carries fully-resolved primitives only (frozen theme
 * contract), so an unresolved reference means the slot is not exactly readable.
 */
export declare function resolveCssVarRefs(value: string, vars: CssVarDecl[], depth?: number): string | null;
/** px/rem length to canonical px; null for any other unit or expression. */
export declare function normalizeLength(value: string): string | null;
/** Pick black or white by the larger WCAG contrast ratio against the accent. */
export declare function contrastingText(accent: string): "#000000" | "#ffffff";