/**
 * Pure, framework-free IANA-timezone helpers, built on `Intl` (no date library).
 *
 * The scheduler renders in a chosen `timeZone` via a "pseudo-local" trick:
 * {@link toZonedLocal} turns an absolute instant into a Date whose *local*
 * wall-clock equals the wall-clock in `timeZone`, so all the existing
 * local-based date math (startOfDay, minuteOfDay, layout) runs unchanged; then
 * {@link fromZonedLocal} converts a user edit back to a real instant. When
 * `timeZone` is undefined every function is the identity on the browser's zone.
 *
 * These functions are DST-aware and take no ambient "now" (safe for the model /
 * headless contexts that forbid `Date.now()`).
 */
export type ZoneParts = {
    year: number;
    month: number;
    day: number;
    hour: number;
    minute: number;
    second: number;
};
/** The wall-clock parts of `instant` in `timeZone` (browser-local if undefined). */
export declare function zoneParts(instant: Date, timeZone?: string): ZoneParts;
/** Milliseconds `timeZone` is ahead of UTC at `instant` (DST-aware; negative west of UTC). */
export declare function zoneOffsetMs(instant: Date, timeZone?: string): number;
/** An instant -> a Date whose LOCAL fields equal its wall-clock in `timeZone`. */
export declare function toZonedLocal(instant: Date, timeZone?: string): Date;
/** The instant whose wall-clock in `timeZone` is the given Y-M-D H:M:S. */
export declare function instantFromWallClock(year: number, month: number, // 1-12
day: number, hour: number, minute: number, second?: number, timeZone?: string, ms?: number): Date;
/** Inverse of {@link toZonedLocal}: a pseudo-local Date -> the real instant. */
export declare function fromZonedLocal(pseudo: Date, timeZone?: string): Date;
/** Short zone name at `instant`, e.g. "EDT" / "GMT+5:30" - for a ruler header. */
export declare function zoneAbbr(instant: Date, timeZone?: string): string;
/** Validate an IANA zone id; returns it if usable, else undefined (falls back to local). */
export declare function normalizeTimeZone(timeZone?: string): string | undefined;