radiantearth/stac-spec ? reverse-engineered prompt

Build me a clean documentation website for the STAC specification, with a simple landing page that explains what STAC is and how it helps people describe and search geospatial data. I want the site to show the core parts of the spec, like Item, Catalog, Collection, Commons, Examples, and Extensions, with easy navigation and readable pages for each section.

Make it feel like a polished open source standards site, with the current version, links to the relevant docs, and a clear path for someone to learn the basics without being overwhelmed. Include example content that shows how these pieces connect together, plus a section for best practices and contribution info.

Please keep the design modern but minimal, make it responsive, and use the existing README content as the main source of truth. If you need anything unclear, look up current docs online first.