/**
 * Determines whether a given container node contains a specific element, traversing through shadow DOM boundaries if necessary.
 * This function extends the behavior of `Node.contains` to support scenarios involving shadow DOM.
 *
 * @param container - The container node to check, typically the document or a specific DOM element.
 * @param element - The target node to verify if it is contained within the container.
 * @returns `true` if the container node contains the target node, including through shadow DOM boundaries; otherwise, `false`.
 */
export declare function deepContains(container: Node, element: Node | null): boolean;