/**
 * Expanded-stack Y offset for toast at `index` (0 = front).
 *
 * @remarks
 * Matches Sonner: sum of natural heights before this toast, plus `index * gap`.
 * Using a uniform `index * gap` alone breaks when toast heights differ.
 */
export declare function expandedToastOffset(index: number, heights: readonly number[], gap: number): number;
/** Total stack height when expanded: all toast heights + gaps between them. */
export declare function expandedStackHeight(heights: readonly number[], gap: number): number;
/**
 * Collapsed peek stack height: front toast + gap peek per visible stacked toast.
 *
 * @remarks
 * `peekCount` is how many toasts are visually revealed (including the front),
 * not the full mounted count — overflow stays hidden until expand.
 */
export declare function collapsedStackHeight(frontHeight: number, peekCount: number, gap: number): number;