Error: The style-loader cannot be used in a non-browser environment

Hi Cory, after resolving the previous command by comparing/contrasting code from your final project code, I am now receiving this error. Have you come across it before?

```
> npm run start

> javascript-development-environment@1.0.0 prestart /Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env
> babel-node buildScripts/startMessage.js

Starting app in dev mode...

> javascript-development-environment@1.0.0 start /Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env
> npm-run-all --parallel security-check lint:watch open:src

> javascript-development-environment@1.0.0 security-check /Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env
> nsp check

> javascript-development-environment@1.0.0 lint:watch /Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env
> npm run lint -- --watch

> javascript-development-environment@1.0.0 open:src /Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env
> babel-node buildScripts/srcServer.js

> javascript-development-environment@1.0.0 lint /Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env
> esw webpack.config.* src buildScripts --color "--watch"

(+) No known vulnerabilities found
✓ Clean (8:09:08 PM)
Hash: bac25d0a7ccc9b2c43c3
Version: webpack 1.13.2
Time: 841ms
Asset Size Chunks Chunk Names
bundle.js 95.3 kB 0 [emitted] main
index.html 1.09 kB [emitted]
chunk {0} bundle.js (main) 34.1 kB [rendered]
[0] multi main 28 bytes {0} [built]
[1] ./src/index.js 395 bytes {0} [built]
[2] ./src/index.css 907 bytes {0} [built]
[3] ./~/css-loader!./src/index.css 229 bytes {0} [built]
[4] ./~/css-loader/lib/css-base.js 1.51 kB {0} [built]
[5] ./~/style-loader/addStyles.js 7.15 kB {0} [built]
[6] ./~/numeral/numeral.js 23.9 kB {0} [built]

ERROR in Error: The style-loader cannot be used in a non-browser environment

- index.js:185 module.exports
/Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env/src/index.js:185:43

- index.js:71 Object.
/Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env/src/index.js:71:37

- index.js:21 __webpack_require__
/Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env/src/index.js:21:30

- index.js:50 Object.
/Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env/src/index.js:50:2

- index.js:21 __webpack_require__
/Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env/src/index.js:21:30

- index.js:41
/Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env/src/index.js:41:18

- index.js:44
/Users/bxberry/dev/js-dev-env/pluralsight-js-dev-env/src/index.js:44:10

- index.js:225 HtmlWebpackPlugin.evaluateCompilationResult
[pluralsight-js-dev-env]/[html-webpack-plugin]/index.js:225:26

- index.js:115
[pluralsight-js-dev-env]/[html-webpack-plugin]/index.js:115:21

Child html-webpack-plugin for "index.html":
Asset Size Chunks Chunk Names
index.html 36.9 kB 0
chunk {0} index.html 34.1 kB [rendered]
[0] ./~/html-webpack-plugin/lib/loader.js!./src/index.js 395 bytes {0} [built]
[1] ./src/index.css 907 bytes {0} [built]
[2] ./~/css-loader!./src/index.css 229 bytes {0} [built]
[3] ./~/css-loader/lib/css-base.js 1.51 kB {0} [built]
[4] ./~/style-loader/addStyles.js 7.15 kB {0} [built]
[5] ./~/numeral/numeral.js 23.9 kB {0} [built]
```

Reproduce the failure with npm run start, then inspect buildScripts/srcServer.js, src/index.js, and webpack.config.* alongside the reported html-webpack-plugin output. Determine which build path is invoking style-loader in the non-browser environment; done means the start command completes without this error.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.