import { LitElement } from 'lit';
import '../popout/Popout.js';
/**
 * Dropdown submenu nests a secondary menu within a parent dropdown.
 * The trigger slot contains the item that opens the submenu, and the default slot contains the submenu items.
 *
 * Supports both hover (non-touch) and click (touch-devices/accessibility) interactions.
 *
 * On small screens, uses mobile stack navigation: tapping a submenu trigger replaces the
 * dropdown's visible content with the submenu's items and shows a back button.
 *
 * @status ready
 * @category action
 *
 * @slot trigger - The element that opens the submenu (typically nord-dropdown-item).
 * @slot - The submenu content items.
 *
 * @fires {NordEvent} open - Forwarded from the internal nord-popout.
 * @fires {NordEvent} close - Forwarded from the internal nord-popout.
 * @fires {CustomEvent} nord-submenu-navigate - Fired when mobile stack navigation activates this submenu.
 */
export default class DropdownSubmenu extends LitElement {
    static styles: import("lit").CSSResult[];
    private popout?;
    /** @internal */
    private mobileActive;
    private readonly popoutId;
    private events;
    private currentTriggerElement;
    private popoutOpen;
    private readonly mobileMediaQuery;
    private isSmallScreen;
    private parentDropdownAlwaysFloating;
    private parentObserver?;
    private get shouldUseMobileStack();
    private get parentDropdown();
    private get isInSubmenuStack();
    private get isDeepestInStack();
    connectedCallback(): void;
    disconnectedCallback(): void;
    render(): import("lit").TemplateResult<1>;
    private handleTriggerSlotChange;
    private handleTriggerMouseEnter;
    private handleTriggerClick;
    private handleTriggerKeydown;
    private handleContentKeydown;
    private handlePopoutOpen;
    private handlePopoutClose;
    private handleParentDropdownMouseOver;
    private closeOtherSubmenus;
    /**
     * Deactivate mobile stack navigation (remove from stack).
     * @internal
     */
    deactivateMobile(): void;
    /**
     * Read trigger text for back button title in Dropdown.
     * @internal
     */
    get label(): string;
    /**
     * Close the submenu programmatically.
     * Returns a promise that resolves when the close animation completes.
     */
    close(): Promise<TransitionEvent | void>;
    /**
     * Navigate into this submenu using mobile stack navigation.
     * @internal
     */
    private navigateIntoSubmenu;
}
declare global {
    interface HTMLElementTagNameMap {
        'nord-dropdown-submenu': DropdownSubmenu;
    }
}