Tailwind CSS is a utility-first CSS framework. Style by combining single-purpose classes in markup.
We use Tailwind v4 only. There is no tailwind.config.js, tailwind.config.ts, or tailwind.config.mjs. Configuration is done in CSS via @import "tailwindcss" and the @theme directive, plus the Vite or PostCSS plugin.
Core principle: Prefer utility classes in markup; extend with @theme and custom CSS when needed. Never suggest or create tailwind.config. or content/theme in a config file.
Set up and use Tailwind CSS v4 only with Next.js (App Router), Vite, or CLI; no tailwind.config.js—theme via @theme in CSS. Use when styling with Tailwind, configuring Tailwind, installing Tailwind, utility classes, @theme, @layer, @utility, or when the user mentions Tailwind CSS or Tailwind v4. Source: enderpuentes/ai-agent-skills.