diff --git a/lib/webpack/shared.cjs b/lib/webpack/shared.cjs
--- a/lib/webpack/shared.cjs
+++ b/lib/webpack/shared.cjs
@@ -1,3 +1,4 @@
+const { VanillaExtractPlugin } = require('@vanilla-extract/webpack-plugin');
 const { CleanWebpackPlugin } = require('clean-webpack-plugin');
 const MiniCssExtractPlugin = require('mini-css-extract-plugin');
 const OptimizeCssAssetsPlugin = require('optimize-css-assets-webpack-plugin');
@@ -77,6 +78,7 @@
     name: 'browser',
     optimization: {
       minimizer: [new TerserPlugin(), new OptimizeCssAssetsPlugin()],
+      sideEffects: true,
     },
     plugins: [
       ...(baseConfig.plugins ?? []),
@@ -102,6 +104,7 @@
           BROWSER: true,
         },
       }),
+      new VanillaExtractPlugin(),
       new MiniCssExtractPlugin({
         filename: 'prod.[contenthash:12].build.css',
       }),
@@ -142,7 +145,8 @@
               options: {
                 ...cssLoader.options,
                 url: false,
-                modules: false,
+                modules: true,
+                sourceMap: true,
               },
             },
           ],