The preview tool for Spectrum CSS is driven by Storybook, a React-driven development environment that allows for in-depth exploration of components as they are being built.
For more information on contributing to the Spectrum CSS project, please see the development documentation (rendered in storybook under the Guides category).
To spin up the preview environment, run the following command:
yarn start
This will start the Storybook server and open a new browser window with the preview environment. From there, you can explore the various components and their states, as well as the documentation for each component. Be sure to run commands from the root of the project.