/** Keep in sync with `--og-duration-stream` / `.og-stream-ink` in styles. */
export declare const INK_FADE_MS: number;
/** @deprecated Use {@link INK_FADE_MS}. */
export declare const WORD_ANIMATION_MS: number;
export type StreamReveal = {
    /** Register the full current source text; new suffix becomes an ink batch. */
    observe(text: string, now: number): void;
    /**
     * CSS animation-delay (ms) for the run covering `offset`, or null when that
     * ink has settled and should render as plain text. Negative = resume mid-fade.
     */
    delayFor(offset: number, now: number): number | null;
    /** True while any batch is still inside its fade window. */
    hasActive(now: number): boolean;
};
export declare function createStreamReveal(): StreamReveal;
type HastText = {
    type: "text";
    value: string;
    position?: {
        start?: {
            offset?: number | undefined;
        } | undefined;
    } | undefined;
};
type HastParent = {
    type: string;
    tagName?: string;
    value?: string;
    children?: HastChild[];
};
type HastChild = (HastText | HastParent) & Record<string, unknown>;
export declare function rehypeStreamReveal(options: {
    reveal: StreamReveal;
    now: number;
}): (tree: HastParent) => void;
export {};