import { LitElement } from 'lit';
/**
 * Semi-transparent backdrop for dimming page content when a secondary
 * navigation dropdown or mobile menu is expanded. Provides a click
 * target that allows users to close all open menus. Managed
 * automatically by `<rh-navigation-secondary>`; avoid using
 * standalone. Screen readers should ignore this element as it serves
 * a purely visual purpose. Keyboard: Escape closes the overlay.
 *
 * @summary Backdrop overlay for expanded secondary navigation menus
 */
export declare class RhNavigationSecondaryOverlay extends LitElement {
    static readonly styles: CSSStyleSheet[];
    /**
     * When `true`, displays the overlay. Managed automatically by the
     * parent `<rh-navigation-secondary>` when dropdowns or the mobile
     * menu expand. Defaults to `false`.
     */
    open: boolean;
}
declare global {
    interface HTMLElementTagNameMap {
        'rh-navigation-secondary-overlay': RhNavigationSecondaryOverlay;
    }
}