The provided text details the technical evolution and implementation of native CSS Nesting, a feature that allows developers to write hierarchical styles directly in the browser. It tracks the specification’s journey from its early 2021 drafts to a stable standard, highlighting key updates like relaxed parsing and the introduction of CSSNestedDeclarations to fix cascade ordering. The sources contrast this native functionality with traditional preprocessors like Sass, explaining how browsers now handle specificity and the ampersand (&) selector without external tools. Additionally, the text explores how nesting integrates with other modern features such as Cascade Layers (@layer) and Scoping (@scope) to improve code maintainability. Finally, it confirms that by 2025/2026, all major browser engines have achieved interoperability, making the feature ready for widespread production use.