/**
 * Shared utility for styled BaseUI primitive wrappers.
 *
 * Merges an Atlantis base class with a consumer-supplied className that may be
 * either a plain string or a BaseUI state-based function
 * (e.g. `className={(state) => state.open ? "open" : ""}`).
 *
 * All styled primitives should import from here rather than defining their own
 * copy, so the type is consistent across the package.
 */
export type PrimitiveClassName<State = void> = string | ((state: State) => string | undefined) | undefined;
export declare function mergeClassName<State>(baseClassName: string, className: PrimitiveClassName<State>): PrimitiveClassName<State>;