/**
 * Story timeline math (spec: "Map Stories / Clock, seek, and the scrub
 * model") — a pure module: step timings in, absolute intervals out. No DOM,
 * no clock, fully unit-testable.
 *
 * Sequencing semantics:
 * - Sequential (default): a step starts when EVERYTHING before it has
 *   finished (max end of all prior steps) — so a short parallel step never
 *   pulls the next step into the middle of a longer one.
 * - `parallel`: joins the PREVIOUS step's start (Animaps' "scenes" without
 *   a grouping element).
 * - `delay` staggers either form's start.
 */
export interface StepTiming {
    /** How long the step's animation runs (ms). 0 = instantaneous state change. */
    duration: number;
    /** Stagger before the step starts (ms), applied after sequential/parallel placement. */
    delay: number;
    /** Start with the previous step instead of after everything so far. */
    parallel: boolean;
}
export interface StepInterval {
    start: number;
    end: number;
}
export interface Timeline {
    intervals: StepInterval[];
    /** Total running time — max end across all steps. */
    total: number;
}
export declare function computeTimeline(steps: readonly StepTiming[]): Timeline;
/**
 * `"800"` / `"800ms"` / `"2s"` → milliseconds. The shared duration grammar
 * for step timings and camera payloads (returns `fallback` on anything
 * unparseable — callers decide whether to warn).
 */
export declare function parseDurationMs(raw: string | number | undefined | null, fallback?: number): number;