In Drupal 8, the folder structure is changed to make it more logical. Everything that ships with Drupal now resides in a core folder including the default themes, which are now contained within the core/themes folder. However, any themes that we download or develop ourselves now reside within the themes folder.

The folder structure comprises the following:

Before we can begin creating our own custom themes, we need to have a better understanding of how themes are configured and exactly how they let Drupal know where to display content and how the content should look.