This can be done by simply adding:

require('./App.css');

(thanks @elmeister who correctly answered this question.)

To enable CSS module in to your app, you don't need to eject create-react-app. You can follow these simple steps described in this link to use CSS module in your project.

But in case if you ejected your create-react-app, then you must find file named

"webpack.config.js"

open this file and find this {test:cssRegex....etc} in line no. 391 and replace to this changes:

Copy            {
              test: cssRegex,
              exclude: cssModuleRegex,
              use: getStyleLoaders({
              importLoaders: 1,
              modules: true,
              localIdentName: '[name]__[local]__[hash:base64:5]'
            }),
            },

Open .js file and import statement like this

Copyimport cssStyleClassName from './MyApp.css';

Then this import statement allow you to do following changes in component tags like this

Copy<div className={cssStyleClassName.styleName}></div>

styleName is what you defined in your MyAppStyle.css file

Copy.styleName{
your properties here...
}

After eject your app, you must restart your local server, sometime changes don't get reflect.

Note In earlier version there were two generated file for production and dev separately. Now in current version one file named "webpack.config.js" file for which you need to concerned for changes. Thank you.