How delete unused styles?

[vaniljs]

• I have searched the issues of this repository and believe that this is not a duplicate.

What problem does this feature solve?

For example, i only needed a Calendar.
But in the final bundle, all styles are taken in general, which makes the style file too large.
How can i take styles just only for the calendar?
Is there an example? I use webpack react sass

What does the proposed API look like?

all version

p.s. I tried to install PurgeCSS Webpack, but it removes the necessary classes.
The only option I can use is to load the bundle into www.purifycss.online , download the result and attach it to the project.
Economy 500kb -> 15kb

My webpack.config.js

const path = require('path');
const TerserPlugin = require("terser-webpack-plugin");
const { CleanWebpackPlugin } = require('clean-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

const glob = require('glob')
const PurgecssPlugin = require('purgecss-webpack-plugin')
const PATHS = {
    src: path.join(__dirname, 'src')
}

module.exports = {
    output: {
        filename: 'script.js',
        path: path.join(__dirname, '/dist')
    },
    devServer: {
        contentBase: [path.resolve(__dirname, "dist"), path.resolve(__dirname, "dist")],
        watchContentBase: true,
        open: true,
    },
    module: {
        rules: [
            {
                test: /\.(js|jsx)$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader'
                }
            },
            {
                test: /\.(sass|css|less)$/i,
                use: [
                    MiniCssExtractPlugin.loader,
                    'css-loader',
                    'postcss-loader',
                    'sass-loader'

                ]
             }
            ]
            }
        ]
    },
    optimization: {
        minimize: true,
        minimizer: [new TerserPlugin({
            terserOptions: {
                format: {
                    comments: false,
                },
            },
            extractComments: false,
        })],
    },
    plugins: [
        new CleanWebpackPlugin(),
        new MiniCssExtractPlugin({
            filename: "[name].css",
        }),
        new PurgecssPlugin({
            paths: glob.sync(`${PATHS.src}/**/*`,  { nodir: true }),
        }),
    ],
}

[zhouxinyong]

i have the same question +1