Yeti is a CSS-first, native, zero-build layout and styling framework for web designers.
Yeti addresses the problem of building coherent websites quickly without requiring a build pipeline or preprocessor. It leverages modern CSS capabilities—container queries, cascade layers, native nesting, light-dark(), dialog, popover, and scroll-snap—to handle layout and styling work that previously demanded JavaScript or Sass. The framework provides named layout primitives and composed recipes configured through data attributes, rather than utility classes. A single token scale derives type and space from a base and ratio, allowing the entire system to recompute when those values change.
Yeti suits designers and teams building for modern browsers who want readable, semantic markup without build tooling overhead. It targets Baseline 2025, meaning it uses features that reached broad browser support by the end of 2025 without guards, with newer features behind @supports queries and fallbacks. If your project requires support for older browsers, this tool is not the right fit. The framework is not a web component library, utility framework, or build-time system, and it does not include full-featured sliders or workarounds for CSS problems that no longer exist.
The framework includes a machine-readable manifest describing every component, from which documentation, type hints, and an MCP server are generated. Accessibility is built in by default, with correct focus handling and ARIA on every component verified in continuous integration.
