diff --git a/webpack.config.js b/webpack.config.js
index 7729035972..9260399396 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -157,6 +157,7 @@ export default {
         minify: true,
         css: true,
         legalComments: 'none',
+        exclude: [new RegExp(`css\\/(${Object.keys(themes).join('|')})\\.css$`)],
       }),
     ],
     splitChunks: {