Shadcn Guideline: Components — Use component variants. Description: Leverage cva variants for consistent styling. Do: Use variant prop for different styles. Don't: Inline conditional classes. Good Example: <Button variant="destructive">. Bad Example: <Button className={isError ? "bg-red-500" : "bg-blue-500"}>. Severity: Medium. Docs: https://ui.shadcn.com/docs/components/button.