import { type CSSProperties, type RefCallback, type RefObject } from "react";
export type PortalTokenStyle = Pick<CSSProperties, "colorScheme"> & Partial<Record<`--${string}`, string>>;
export declare const PORTAL_SOURCE_INLINE_SIZE = "--og-portal-source-inline-size";
/**
 * A callback ref that publishes the currently mounted source element through
 * React state. Unlike a bare mutable ref, late mounts and replacements cause
 * consumers to render and restart their observers without polling.
 */
export declare function usePortalTokenSource<T extends HTMLElement>(): {
    source: T | null;
    currentRef: RefObject<T | null>;
    ref: RefCallback<T>;
};
/**
 * Copy the effective SDK tokens across a portal boundary. A locally themed or
 * rebranded embed cannot rely on CSS inheritance once a portal mounts under
 * `<body>`. Ancestor theme/class/style mutations and OS color-scheme changes
 * keep the copied values live.
 */
export declare function usePortalTokenStyle(source: HTMLElement | null): PortalTokenStyle;