old_contents: const webpack = require('webpack');
  const cssnext = require('postcss-cssnext');
  const precss = require('precss');
  const path = require('path');
  
  module.exports = {
    entry: './main.js',
    output: {
      path: path.join(__dirname, 'dist'),
      filename: 'index.js',
      publicPath: '/dist/'
    },
    module: {
      loaders: [
        {
          test: /\.jsx?$/,
          exclude: /node_modules/,
          loader: 'babel',
          query: {
            presets: ['es2015', 'stage-0', 'react', 'react-hmre'],
          }
        },
        {
          test: /\.css$/,
          loader: 'style!css!postcss'
        }
      ]
    },
    postcss: function () {
      return [
        precss,
        cssnext
      ];
    }
  }
  
new_contents: const cssnext = require('postcss-cssnext');
  const precss = require('precss');
  const path = require('path');
  
  module.exports = {
    entry: './main.js',
    output: {
      path: path.join(__dirname, 'dist'),
      filename: 'index.js',
      publicPath: '/dist/'
    },
    module: {
      loaders: [
        {
          test: /\.jsx?$/,
          exclude: /node_modules/,
          loader: 'babel',
          query: {
            presets: ['es2015', 'stage-0', 'react', 'react-hmre'],
          }
        },
        {
          test: /\.css$/,
          loader: 'style!css!postcss'
        }
      ]
    },
    postcss: function () {
      return [
        precss,
        cssnext
      ];
    }
  }
  
subject: remove require webpack in webpack.config.js