The document discusses implementing SMACSS (Scalable and Modular Architecture for CSS) principles in Drupal 8 CSS organization as a best practice, emphasizing a flexible structure rather than a rigid framework. It outlines how to organize base, layout, module, state, and theme styles effectively, and highlights the importance of separating styles into different files for better management. The document also notes the role of CSS preprocessors like Sass in maintaining consistency across styles.