/**
 * Omits properties that starts with `$` (Styletron)
 * @param $props properties
 */
export declare const omit$props: ($props: Record<string, unknown>) => Record<string, unknown>;
/**
 * Prefixes property names with `$` (Styletron)
 * @param props properties
 */
export declare const add$props: (props: Record<string, unknown>) => Record<string, unknown>;
/**
 * Recursively extract css value from css variable value
 * { ui01: 'var(--spr-ui-01, #FFF)' } -> { ui01: '#FFF' }
 *
 * Jest does not recognize css variables, this utility can help convert theme object.
 *
 * @param value
 */
export declare const covertCSSVariablesToValue: <T extends string | object>(value: T) => T;
export declare const themeTokenToHex: (token: string) => string | null;
/**
 * Converts hexadecimal color to RGB or RGBA (if alpha is provided)
 * @param hex hexadecimal color
 * @param alpha opacity
 */
export declare const hex2rgb: (_hex: string, alpha?: string | undefined) => string | null;