export declare const backtopProps: {
    visibilityHeight: {
        type: NumberConstructor;
        default: number;
    };
    right: {
        type: NumberConstructor;
        default: number;
    };
    bottom: {
        type: NumberConstructor;
        default: number;
    };
    target: {
        type: StringConstructor;
        default: string;
    };
};