/**
 * Build a list of focusable elements inside a container (same selector used by
 * the fileupload preview modals and the global header mega menu). Hidden
 * elements are filtered out.
 */
export declare function getFocusableElements(container: HTMLElement | null | undefined): HTMLElement[];
/**
 * Like {@link getFocusableElements}, but descends open shadow roots, treats a
 * native `<summary>` as focusable, and skips content hidden inside a collapsed
 * `<details>`. Returned in flattened tree order. Use this when the container may
 * hold web components or `<details>` accordions (e.g. the header mega menu).
 */
export declare function getFocusableElementsDeep(container: HTMLElement | null | undefined): HTMLElement[];
/** Resolve the genuinely focused element, piercing nested open shadow roots. */
export declare function getDeepActiveElement(doc?: Document): HTMLElement | null;
/**
 * Keyboard handler that wraps Tab / Shift-Tab focus around the first and last
 * focusable elements inside a container. Returns `true` if the event was handled.
 *
 * Call from a `keydown` listener on the modal root.
 */
export declare function trapTabInside(event: KeyboardEvent, container: HTMLElement | null | undefined): boolean;