Responsive images ensure the browser downloads the most appropriate image size for the user’s device and layout, improving performance and visual quality. In Drupal 10 and 11, responsive images are handled through Image Styles, Responsive Image Styles, and the Responsive Image module.

Component-Driven Theming is a modern frontend architecture approach where UI is built using reusable, self-contained components instead of large monolithic templates. In Drupal 10 and 11, this approach aligns with Twig templating, libraries, render arrays, and design system practices.

In Drupal 10 and 11, CSS and JavaScript are managed through the Library API.

In Drupal 10 and Drupal 11, regions define the structural placeholders of a page. They act as containers where blocks are placed and rendered. While themes control markup and styling, regions define the structural layout boundaries.

In Drupal 10 and Drupal 11, the theme layer is responsible for presentation — not business logic. Drupal follows a strict separation of concerns: modules handle data and logic, while themes handle markup and styling.