yeti

Yeti is a CSS-first, native, zero-build layout and styling framework aimed at web designers, developed by Foundation as the successor to Foundation for Sites. It is currently in development at version 7.0.0-alpha, so class names, attributes and tokens may still change before a beta release. Foundation for Sites 6 continues on a separate v6 branch with bug fixes, and the foundation-sites npm package keeps publishing 6.x from it. The framework is delivered as a single stylesheet that can be linked directly, with no Sass, Node or bundler required to use it. It can still be composed into an existing build pipeline if one exists, but it never demands one. Its design leans on modern native CSS capabilities such as container queries, cascade layers, native nesting, light-dark(), dialog, popover and scroll-snap, replacing work that previously required JavaScript or a preprocessor. Rather than utility classes, Yeti provides intent-based layout primitives and composed recipes configured through a small number of data attributes. Typography and spacing derive from one base value and one ratio at runtime, so changing the ratio recomputes the whole system. Components are described as accessible by default, with focus handling and ARIA checked in CI. A machine-readable manifest describes every component, and the documentation, type hints and an MCP server are generated from it, which the project frames as making the framework legible to agents. The project explicitly is not a web component library, a utility framework or a build-time system, and it ships no polyfills. Browser support targets Baseline 2025: features that reached Baseline by the end of 2025 are used without guards, while newer features sit behind @supports with fallbacks. The current alpha includes tokens, a reset, a base layer, seventeen layout primitives, three recipes, the first eight components and two example themes. Users can link the unbuilt source directly and write plain HTML, or clone the repository, install dependencies, install Playwright and run the test and fixture commands to browse examples locally. Contributions are handled through CONTRIBUTING.md, Discussions and issue templates. The license is the Functional Source License 1.1 with an MIT future license, permitting use, copying, modification and redistribution except as a competing product, with each release becoming plain MIT two years after shipping.