Preview.js automatically loads your PostCSS config, so Tailwind should just work.

If Tailwind isn't detected automatically, make sure that you have a postcss.config.js file (or equivalent), such as:

module.exports = {
  plugins: {
    tailwindcss: {},
    autoprefixer: {},

If Tailwind still isn't detected by Preview.js, you may need to set up a wrapper that imports your global CSS.