/**
 * duration - pure parse/format helpers behind <SvDurationInput>. The canonical
 * value is a number of MINUTES; these convert to/from the human forms people
 * type ("1h 30m", "1:30", "90"). Framework-free + pure so they are unit-tested
 * directly.
 */
/**
 * Parse a human duration to minutes, or `null` if unparseable. Accepts:
 * - `h:mm`         e.g. "1:30" -> 90
 * - unit form      e.g. "1h 30m", "1.5h", "45m" -> 90 / 90 / 45
 * - a bare number  e.g. "90" -> 90 (treated as minutes)
 */
export declare function parseDuration(input: string): number | null;
/** Format minutes as `h:mm` (colon) or `Nh Nm` (units). Empty for invalid input. */
export declare function formatDuration(minutes: number, style?: 'colon' | 'units'): string;