diff --git a/lib/webpack/shared.cjs b/lib/webpack/shared.cjs
--- a/lib/webpack/shared.cjs
+++ b/lib/webpack/shared.cjs
@@ -135,6 +135,7 @@
         },
         {
           test: /node_modules\/.*\.css$/,
+          sideEffects: true,
           use: [
             cssExtractLoader,
             {