How do you create application to use scss? What changed for Angular 6?

This is how the style config in the CLI v1.x looks like in .angular-cli.json file.

"defaults": {
  "styleExt": "scss",
  "component": {}
}

But if you take a look into a config schema of angular.json file in version 6, you will no longer find this config anymore. To use SCSS, simply import you scss files (the default value is ‘src/styles.scss’) in your project level in an angular.json file like this.

{
  ...
  projects: {
    [your_project_name]: {
      ...
      architect: {
        build: {
          ...
          options: {
            styles:{
              "src/styles.scss"
            }
          }
        }
      }
    }
  }
}