sass-loader-config.js

{
    test: /\.scss$/, // change here -------------------------------------------------------------------------> change 1
    use: [
        require.resolve('style-loader'),
        {
            loader: require.resolve('css-loader'),
            options: {
                importLoaders: 1,
            },
        },
        { // ------------------------------------------------------------------------------------------------> change 2
            loader: require.resolve('sass-loader'), // added this loader
        },
        {
            loader: require.resolve('postcss-loader'),
            options: {
                // Necessary for external CSS imports to work
                // https://github.com/facebookincubator/create-react-app/issues/2677
                ident: 'postcss',
                plugins: () => [
                    require('postcss-flexbugs-fixes'),
                    autoprefixer({
                        browsers: [
                            '>1%',
                            'last 4 versions',
                            'Firefox ESR',
                            'not ie < 9', // React doesn't support IE8 anyway
                        ],
                        flexbox: 'no-2009',
                    }),
                ],
            },
        },
    ],
}