On June 15 and 17 we hosted our CLSA Community Meetup that featured a deep dive into the Pega Digital Experience Framework which includes the Cosmos design system, the React based UI, our current rules based UI and hybrid UI.
In the below recording you will hear Vinay Kamath (Sr. Director, User Interface Technology) talk about those different UI options, the advantages, migration paths and when to use what. Vinay also shares the latest updates around how to make you application accessible according to the latest W3C WCAG guidelines. At the end of the recording there is an extensive Q&A with the questions that were asked along the presentation by the participants.
Below you will also find the handout of the slides.
@Chunzhi_Hong I would say the best place to go is https://design.pega.com. Not only does this allow you to design a Cosmos application but also the Cosmos components are listed with demo's of how it looks in the case manager portal. Both the theme Cosmos and Cosmos React implement this design.
There is currently not a downloadable demo application. However the product team is working on such an application that will be made available. Stay tuned.