A theme is a kit with a look
Design tokens, blocks and page templates in one package, with screenshots. Preview one, then install it on your site from the registry: the tarball is verified against the signed index before a byte of it is used.
Most installed first. Every theme passed the automated checks and shipped at least one screenshot.
No themes have been published yet. Publish the first one with spillway publish from a folder holding a kit.json with "kind": "theme".
Install a theme with spillway kit install <name> --registry https://spillwaycms.com, or POST /api/kits/install-from-registry { "name": "<name>" } with a token that carries users.manage. The site downloads the tarball, checks its sha256 against the signed index and runs the kit installer; types, pages and menus that already exist are left alone.