Understanding the theming system
UI styling is the most customized part of an application, and you have plenty of options. You can start with one of the UI kits such as Bootstrap, Tailwind CSS, or Bulma as the base for your application UI. You can then build a design language or buy a pre-built, cheap UI theme from a theme market. If you are building an independent application, you can make your selections and create your UI pages and components based on these selections. Your pages and styling don't have to be compatible with another application.
On the other hand, if you want to build a modular application where each module's UI is independently developed (probably by a separate team) where the modules come together at runtime as a single application, you need to determine a design standard that should be implemented by all the module developers so that you have a consistent user interface.
Since ABP Framework provides a modular infrastructure, it provides a theming...