Install a React component library, import a Button , render it. The label shows up and the click handler fires, but the thing looks like a gray browser default. The console is quiet and the build is green. I reproduced this in clean projects while working on MoonUI, a component library built on Radix and Tailwind. The components were not broken. My Tailwind setup just had no idea they existed, and then no idea what their colors meant. Those are two separate problems with two separate fixes, ...