Using webpack to compress css problems

Please take a look at this code. The packaged css can be separated but not compressed. Minimize: true has been set

const webpack = require("webpack");
const HtmlWebpackPlugin = require("html-webpack-plugin");
const ExtractTextPlugin = require("extract-text-webpack-plugin");
const CleanWebpackPlugin = require("clean-webpack-plugin");
let pathsToClean = [
    "build"
  ]
module.exports = {
    entry: __dirname + "/app/main.js",//
    output: {
        path: __dirname + "/build",
        filename: "bundle.js"
    },
    devtool: false,
    devServer: {
        contentBase: "./public",//
        historyApiFallback: true,//
        inline: true//
    },
    module: {
        rules: [
            {
                test: /(\.jsx|\.js)$/,
                use: {
                    loader: "babel-loader"
                },
                exclude: /node_modules/
            },
            {
                test: /\.(less|css)$/,
                use: ExtractTextPlugin.extract({
                  fallback: "style-loader",
                  //resolve-url-loader may be chained before sass-loader if necessary
                  use: [{
                    loader: "css-loader",
                    options: {
                      minimize: true //css
                    }
                  }, {
                    loader: "postcss-loader"
                  },{
                    loader:"less-loader"
                  }]
                })
                
            }
        ]
    },
    plugins: [
        new webpack.BannerPlugin(""),
        new HtmlWebpackPlugin({
            template: __dirname + "/app/index.html"//new 
        }),
        new CleanWebpackPlugin(pathsToClean),
        new ExtractTextPlugin("css/style_[chunkhash].css"),
        new webpack.optimize.UglifyJsPlugin({ //js
          compress: {   //
            dead_code: true,  //
            warnings: false,   //
            loops: true //dowhile  for
          },
          except: ["$super", "$", "exports", "require"]  //,
        })
    ],
};
Css
Mar.30,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3532f-2bf80.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3532f-2bf80.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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