You'll see a new little button in the Project Editor (on the bar between the code editors and the preview) called Logs. The whole purpose of it is to give you some insight into the processing that your project is doing when you save files. Save a .scss file? You'll see START SASS, any errors that might happen while it's doing that, and FINISHED SASS when it's done.

When you use preprocessors of any kind in CodePen Projects, errors are possible. We want to make it as clear as possible when that happens, so errors are exposed in three ways:

  1. Inline in the file itself, as close to the line that has the error as we can get you.
  2. Red dots in the sidebar, indicating the errored file and all folders that contain it. That way if a file is a few levels deep, you'll always be able to follow the dots down to find it.
  3. In the new logs, which show you the complete error output and includes a button to jump to that file.