import { Factory, CssKnownProps, CssRule, CssVars } from '@cssfn/core';
export interface BackdropVars {
    /**
     * Backdrop's scroll top position.
     */
    scrollTop: any;
    /**
     * Backdrop's scroll left position.
     */
    scrollLeft: any;
}
export interface BackdropStuff {
    backdropRule: Factory<CssRule>;
    backdropVars: CssVars<BackdropVars>;
}
export interface BackdropConfig {
    scrollTop?: CssKnownProps['top'];
    scrollLeft?: CssKnownProps['left'];
}
/**
 * Uses Modal's backdrop.
 * @param config  A configuration of `backdropRule`.
 * @returns A `BackdropStuff` represents the backdrop rules.
 */
export declare const usesBackdrop: (config?: BackdropConfig) => BackdropStuff;