/**
 * View Transition API helpers for `data-view-transition` markup and safe root defaults.
 * @module
 */
/**
 * Whether a document tree contains elements that participate in named view transitions.
 */
export declare function documentHasNamedViewTransitions(doc: Document): boolean;
/**
 * Whether SPA navigation should use `startViewTransition` (old or incoming page).
 */
export declare function navigationHasNamedViewTransitions(current: Document, incoming: Document): boolean;
/**
 * Injects persisted CSS that opts the document out of the root view-transition group.
 *
 * @remarks
 * Uses `data-eco-persist` so head morphing does not drop the stylesheet between navigations.
 * Named `data-view-transition` morph / fade rules live in a separate dynamic style tag.
 */
export declare function ensureRootViewTransitionStyles(): void;
/**
 * Assigns `view-transition-name` from `data-view-transition` and injects morph styles.
 *
 * @remarks
 * Elements without `data-view-transition-animate="fade"` get a geometric morph:
 * the old snapshot is hidden so cross-fade ghosting does not appear.
 */
export declare function applyViewTransitionNames(): void;
/**
 * Clears inline transition names and dynamic morph styles after a transition ends.
 */
export declare function clearViewTransitionNames(): void;