We can take a closer look at Classy by navigating to the core/themes/classy
folder of our Drupal instance. At first glance, the theme structure of Classy is quite organized. It is well-structured with folders for CSS, images, and a multitude of Twig templates. Each template has been organized based on its functionality as follows:
Everything so far screams best practices and is one of the major benefits of creating a subtheme that uses Classy as a base theme. However, we can still add our own regions, libraries, and Twig templates as we would for any other theme. However, in some cases, we may find ourselves also needing to override libraries with our own CSS or JS without modifying any assets directly located in the base theme.