can not found backgound-image

build/webpack.prod.conf.js

@@ -33,7 +33,7 @@ var webpackConfig = merge(baseWebpackConfig, {
     }),
     new webpack.optimize.OccurrenceOrderPlugin(),
     // extract css into its own file
-    new ExtractTextPlugin(utils.assetsPath('css/[name].[contenthash].css')),
+    new ExtractTextPlugin('[name].[contenthash].css'),
     // generate dist index.html with correct asset hash for caching.
     // you can customize output by editing /index.html
     // see https://github.com/ampedandwired/html-webpack-plugin