Building an application that works with TUI, web, and desktop is possible but there are some differences you need to keep in mind. The TUI renderer has a different scaling factor than the web renderer. One pixel is one character and Widgets have start with a capital letter with the web renderer, but for the attribute and elements that the TUI renderer supports the goal is to behave as close to possible to the web implementation. There are some differences that will likely remain because of the differences of the terminal platform, but we would like to continue working on minimizing these differences in the future.

I assume you can easily case for rendering specialization?

You can use rust's feature flags with one flag per renderer to specialize based on the renderer