The final file we need to create for our playground component is that which will house its styles. In your IDE, right-click the playground directory, select New File, and enter playground.component.css as the name. The playground.component.css file is also required because we've passed it into our component decorator as one of the parameters. Enter the following code in this file:

/* Nothing here yet. This is a placeholder file that we may use later. */

The preceding code is self-explanatory. We don't have any styles in this file yet—but it's good to create at least one CSS file for every component that you create.