I was discovered this css framework for my projects to replace Bootstrap, and I loved. This is a smart unopinionated css framework who give us a lot of flexibility and maybe can let UI designers more powerfull to create lot of themes for NodeBB. Leaving ACP with bootstrap, this can be used only for user frontend. It is easy to "emulate" BS componentes at first glance on migration (there are few utilities for this), so we can switch to TailwindCSS getting the same look and feel. That's all, only a suggestion.