import type { Map as MaplibreMap } from 'maplibre-gl';
/**
 * Find the first symbol (label) layer in the map's current style, or undefined.
 * Symbol layers are the basemap's place names, road labels, etc. Inserting a
 * data layer *before* this id keeps every label above the data.
 *
 * @see https://docs.mapbox.com/mapbox-gl-js/example/geojson-layer-in-stack/
 */
export declare function findFirstSymbolLayerId(map: MaplibreMap): string | undefined;
/** Options for {@link emphasizePlaceLabels}. */
export interface EmphasizeLabelsOptions {
    /** Text color for place labels. Default `#1a1a1a` (near-black). */
    textColor?: string;
    /** Halo color. Default solid white. */
    haloColor?: string;
    /** Halo width, in px. Default `1.6`. */
    haloWidth?: number;
}
/**
 * Darken the basemap's populated-place labels (cities, towns, capitals, …) and
 * give them a strong white halo so they stay legible on top of colored data
 * overlays.
 *
 * The default protomaps style fades place labels with a zoom-driven
 * `text-opacity` (city labels only reach full strength around zoom 9), so this
 * also pins `text-opacity` to 1 — otherwise the near-black color reads as gray
 * at the low-to-mid zooms typical of a choropleth.
 *
 * Targets the `place` source-layer symbol layers of the default Reuters
 * protomaps style. On a style that doesn't have them it's a **no-op** (the
 * per-layer checks and `try/catch` make it degrade gracefully), so it's safe to
 * call regardless of `styleUrl`.
 */
export declare function emphasizePlaceLabels(map: MaplibreMap, opts?: EmphasizeLabelsOptions): void;