fix(map): prevent theme CSS from collapsing circle-marker SVG to 0×0

src/css/custom.css

@@ -4,6 +4,15 @@
     font-size: 12px;
 }
 
+/* Prevent themes that set svg { max-width: 100%; height: auto; } from
+   collapsing Leaflet renderer SVGs to 0×0. The pane <div> is position:absolute
+   with no explicit width, so 100% resolves to 0, wiping out the SVG dimensions
+   that Leaflet sets via attributes. */
+.leaflet-pane > svg {
+    max-width: none !important;
+    height: auto !important;
+}
+
 /* map toggle work with twenty twenty template */
 
 /* .leaflet-control-layers-list {

src/map-engine/Spotmap.ts

@@ -221,7 +221,12 @@ export class Spotmap {
             this.layers,
             dbg
         );
-        const canvasRenderer = L.svg( { pane: 'markerPane' } );
+        // Use a dedicated pane (z-index 450, above overlayPane 400) so that
+        // circle-dot markers render above polylines. Avoids theme CSS targeting
+        // .leaflet-marker-pane which can set the SVG to 0×0.
+        this.map.createPane( 'spotmapCirclePane' );
+        ( this.map.getPane( 'spotmapCirclePane' ) as HTMLElement ).style.zIndex = '450';
+        const canvasRenderer = L.svg( { pane: 'spotmapCirclePane' } );
         this.markerManager = new MarkerManager(
             this.map,
             this.layers,

src/map-engine/__tests__/Spotmap.test.ts

@@ -57,6 +57,10 @@ let capturedGpxEmitter: ReturnType< typeof createEventEmitter > | null;
 function buildLeafletMock() {
     capturedGpxEmitter = null;
 
+    const mockPane = Object.assign( document.createElement( 'div' ), {
+        style: { zIndex: '' },
+    } );
+
     const mockMap = {
         scrollWheelZoom: { enable: jest.fn(), disable: jest.fn() },
         once: jest.fn(),
@@ -69,6 +73,8 @@ function buildLeafletMock() {
         invalidateSize: jest.fn(),
         removeLayer: jest.fn(),
         attributionControl: { setPrefix: jest.fn() },
+        createPane: jest.fn(),
+        getPane: jest.fn().mockReturnValue( mockPane ),
     };
 
     const mockLayerControl = {