import { LitElement } from 'lit';
import { Placement } from '@floating-ui/dom';
export declare class LitCustomPopper extends LitElement {
    open: boolean;
    placement: Placement;
    keepMounted: boolean;
    private referenceElement;
    private popperElement;
    static styles: import("lit").CSSResult;
    connectedCallback(): void;
    disconnectedCallback(): void;
    firstUpdated(): void;
    updated(changedProperties: Map<string | number | symbol, unknown>): void;
    private updatePopperPosition;
    private handleOutsideClick;
    private closePopper;
    render(): import("lit-html").TemplateResult<1>;
}
declare global {
    interface HTMLElementTagNameMap {
        'lit-custom-popper': LitCustomPopper;
    }
}