next.config.js

// next.config.js
const withLess = require('@zeit/next-less');

module.exports = withLess({
  cssModules: true,
  cssLoaderOptions: {
    importLoaders: 1,
    localIdentName: "[local]___[hash:base64:5]",
  },
  webpack: config => {
    // Fixes npm packages that depend on `fs` module
    config.node = {
      fs: 'empty'
    };

    return config;
  }
})