diff --git a/package.json b/package.json
index 0b9d261758..2247fd19d8 100644
--- a/package.json
+++ b/package.json
@@ -83,5 +83,5 @@
   "eslintConfig": {
     "extends": "openlayers"
   },
-  "sideEffects": false
+  "sideEffects": ["ol.css"]
 }