CSSstä

CSSstä is a proposed stylesheet language designed to extend CSS with modular components and predictable scoping for large-scale web applications. Conceived to address fragmentation in large design systems, CSSstä aims to provide a consistent method for authoring, composing, and theming styles while remaining compatible with standard CSS through compilation.

Core goals include improved maintainability, clearer ownership of styles, and safer reuse. It introduces a component-centric workflow where styles are authored as reusable blocks, each with its own scope, dependencies, and tokens. The approach emphasizes theming via design tokens and a centralized token registry, enabling teams to switch palettes without touching individual rules.

Key concepts include a modular import system, a token-based design system, and restricted scoping across modules. CSSstä supports composition, where a component inherits or combines styles from other components; it provides deterministic cascading through explicit precedence rules; and it offers tooling to validate dependencies and prevent style leakage. The syntax is designed to compile to standard CSS so existing browsers and tooling remain compatible.

Tooling and adoption: CSSstä is typically implemented via a transpiler that converts CSSstä modules into plain CSS with source maps. Build pipelines may integrate linters, type-checkers, and IDE support. The specification remains experimental, with usage concentrated in design-system workflows, prototyping, and educational projects rather than widespread production deployment.