In 2021, the development of Emby themes was decentralized, but two main hubs emerged:

While Emby had a built-in "Dark Mode," 2021 saw the rise of "True Black" or "AMOLED" themes.

The year 2021 marked a significant transitional period for the Emby media server community. While the official Emby client ecosystem moved toward a more unified, locked-down architecture, the user base—particularly those utilizing web browsers and Android TV—drove a resurgence in "Custom CSS" usage. This paper explores the dominant CSS themes of 2021, the rise of the "Stylus" extension as a primary delivery method, and the aesthetic trends that defined the user experience during this period.

Theming Emby in 2021 was not without difficulties.