use relative links

styles/osm-dark/style.json

@@ -28,8 +28,8 @@
       "url": "https://tileserver.maps.metager.de/data/openmaptiles.json"
     }
   },
-  "sprite": "https://tileserver.maps.metager.de/styles/osm-dark/sprite",
-  "glyphs": "https://tileserver.maps.metager.de/fonts/{fontstack}/{range}.pbf",
+  "sprite": "{styleJsonFolder}/sprite",
+  "glyphs": "{fontstack}/{range}.pbf",
   "layers": [
     {
       "id": "background",