I have map that shows polygon for some regions. It works fine, but I need to add color for the whole map and make polygon transparent … like the entire map is disabled but polygon is available.

I tried to add base layer

const baseLayer = {
    id: "base",
    type: "background",
    paint: {
      "background-color": "#98b",
      "background-opacity": 0.3, 
    },
  };

  // Layer for the transparent polygon
  const polygonLayer = {
    id: "selected",
    type: "fill",
    source: "selected",
    layout: {},
    paint: {
      "fill-color": "#98b",
      "fill-opacity": 0.0, 
      "fill-outline-color": "#000", 
    },
  };


return (
    <Map
      ref={mapRef}
      ...
    >
      <Layer {...baseLayer}/>
      {geojson && (
        <Source id="selected" type="geojson" data={geojson}>
          <Layer {...polygonLayer} />
        </Source>
      )}

     ...
    </Map>
  );

But the problem is that nothing happens, only if I change polygonLayer opacity "fill-opacity": 0.2 or higher I can see the polygon because the color “stronger”, but I need transparent part.
Any idea how to make it works?