/**
 * Locale Resolution Utilities
 *
 * Cascade for resolving locale/language preferences, so developers can set it
 * per-component, per-section, per-page, or fall back to the browser default.
 */
/**
 * Get the effective locale for an element using the resolution cascade.
 *
 * Resolution order:
 * 1. Explicit locale attribute on the element
 * 2. Closest ancestor element with a `lang` attribute
 * 3. Document root element's `lang` attribute
 * 4. Browser's navigator.language
 * 5. Fallback to 'en-US'
 *
 * @param element - The element to get locale for
 * @param explicitLocale - Optional explicit locale value (from component's locale attribute)
 * @returns The resolved locale string (e.g., 'en-US', 'fr-FR')
 *
 * @example
 * ```html
 * <html lang="en-US">
 *   <div lang="fr-FR">
 *     <ty-input></ty-input>              <!-- Uses 'fr-FR' -->
 *     <ty-input locale="de-DE"></ty-input>  <!-- Uses 'de-DE' -->
 *   </div>
 *   <ty-input></ty-input>                <!-- Uses 'en-US' -->
 * </html>
 * ```
 */
export declare function getEffectiveLocale(element: HTMLElement, explicitLocale?: string | null): string;
/**
 * Create a MutationObserver to watch for lang attribute changes.
 * Useful for components that need to react to dynamic locale changes.
 *
 * @param element - The element to observe
 * @param callback - Function to call when lang changes
 * @returns Cleanup function to disconnect the observer
 *
 * @example
 * ```typescript
 * class TyInput extends HTMLElement {
 *   private _localeObserver?: () => void;
 *
 *   connectedCallback() {
 *     this._localeObserver = observeLocaleChanges(this, () => {
 *       this.render(); // Re-render when locale changes
 *     });
 *   }
 *
 *   disconnectedCallback() {
 *     this._localeObserver?.();
 *   }
 * }
 * ```
 */
export declare function observeLocaleChanges(element: HTMLElement, callback: (newLocale: string) => void): () => void;