Global styles define application-wide CSS including resets, typography, utility classes, and theme variables shared across all components. As the creator of CoreUI, a widely used open-source UI library, I’ve architected global style systems in Angular applications throughout my 11 years of frontend development. The most maintainable approach is using styles.scss as the global stylesheet with SCSS variables, mixins, and partials for organization. This method centralizes theme configuration, enables consistent styling across components, and supports SCSS preprocessing for advanced features.