diff --git a/package.json b/package.json
index ee9ddb209..4a8c1fc33 100644
--- a/package.json
+++ b/package.json
@@ -122,6 +122,12 @@
     "webpack-cli": "^3.3.2",
     "webpack-dev-server": "3.3.1"
   },
+  "sideEffects": [
+    "es/**/style/*",
+    "lib/**/style/*",
+    "*.css",
+    "*.less"
+  ],
   "vetur": {
     "tags": "vetur/tags.json",
     "attributes": "vetur/attributes.json"