import { MutableRefObject, RefObject } from 'react';
export type ScrollDirection = 'up' | 'down' | 'idle';
/**
 * Detects the scroll direction from the nearest scrollable ancestor.
 * @param scrollContainerRef - Optional explicit scroll container. If omitted, the
 *   hook walks the DOM from the returned `elementRef` to find the nearest scrollable
 *   ancestor, falling back to `window`.
 * @returns A tuple of `[elementRef, direction]`. Attach `elementRef` to the
 *   component's root element to enable auto-detection.
 * @remarks
 * - When `prefers-reduced-motion` is active, direction is always `'idle'`.
 */
export declare function useScrollDirection(scrollContainerRef?: RefObject<Element | null>): [MutableRefObject<Element | null>, ScrollDirection];