import { LitElement, PropertyValues } from 'lit';
export declare class WebUiBackTop extends LitElement {
    static styles: import('lit').CSSResult;
    get scrollBehavior(): 'smooth' | 'auto';
    set scrollBehavior(value: string);
    private _scrollBehavior;
    visible: boolean;
    scrollTarget: HTMLElement | Window;
    get threshold(): number;
    set threshold(v: number);
    private _threshold;
    private eventController?;
    connectedCallback(): void;
    disconnectedCallback(): void;
    protected willUpdate(props: PropertyValues): void;
    private get target();
    private onScrollTarget;
    private computeVisible;
    toTop(): void;
    private onEnter;
    render(): import('lit').TemplateResult<1>;
}
declare global {
    interface HTMLElementTagNameMap {
        'web-ui-back-top': WebUiBackTop;
    }
}