CssSyntaxError : no matching @tailwind base

[AndyOooh]

Hi,

I am trying to set up a project using tailwind.

Following the guides I get this error:

 ⨯ ./node_modules/.pnpm/nextra-theme-docs@4.2.10_@types+react@19.0.8_next@15.1.7_react-dom@19.0.0_react@19.0.0__react_jcwsz5gmjztkm2qbaf4zzg3uf4/node_modules/nextra-theme-docs/dist/style.css
Error evaluating Node.js code
CssSyntaxError: /Users/andy/Projects/yodl/yapps/my-project/node_modules/.pnpm/nextra-theme-docs@4.2.10_@types+react@19.0.8_next@15.1.7_react-dom@19.0.0_react@19.0.0__react_jcwsz5gmjztkm2qbaf4zzg3uf4/node_modules/nextra-theme-docs/dist/style.css:122:1: `@layer base` is used but no matching `@tailwind base` directive is present.
    [at Input.error (turbopack://[project]/node_modules/.pnpm/postcss@8.5.2/node_modules/postcss/lib/input.js:109:16)]
    [at AtRule.error (turbopack://[project]/node_modules/.pnpm/postcss@8.5.2/node_modules/postcss/lib/node.js:145:32)]
    [at normalizeTailwindDirectives (/Users/andy/Projects/yodl/yapps/my-project/node_modules/.pnpm/tailwindcss@3.4.17/node_modules/tailwindcss/lib/lib/normalizeTailwindDirectives.js:72:32)]
    [at /Users/andy/Projects/yodl/yapps/my-project/node_modules/.pnpm/tailwindcss@3.4.17/node_modules/tailwindcss/lib/processTailwindFeatures.js:29:98]
    [at plugins (/Users/andy/Projects/yodl/yapps/my-project/node_modules/.pnpm/tailwindcss@3.4.17/node_modules/tailwindcss/lib/plugin.js:38:69)]
    [at LazyResult.runOnRoot (turbopack://[project]/node_modules/.pnpm/postcss@8.5.2/node_modules/postcss/lib/lazy-result.js:329:16)]
    [at LazyResult.runAsync (turbopack://[project]/node_modules/.pnpm/postcss@8.5.2/node_modules/postcss/lib/lazy-result.js:258:26)]
    [at LazyResult.async (turbopack://[project]/node_modules/.pnpm/postcss@8.5.2/node_modules/postcss/lib/lazy-result.js:160:30)]
    [at LazyResult.then (turbopack://[project]/node_modules/.pnpm/postcss@8.5.2/node_modules/postcss/lib/lazy-result.js:404:17)]
    [at process.processTicksAndRejections (node:internal/process/task_queues:105:5)]

That's when using
tailwindcss: {},
As the postcss plugin.
When using:
"@tailwindcss/postcss": {},
The project compiles but tw classes aren't applied.

Edit:
Created this codesanbox:
https://codesandbox.io/p/github/AndyOooh/nextra_tw_issue/main?import=true

Files:

// src/mdx-components.js
import { useMDXComponents as getThemeComponents } from "nextra-theme-docs"; // nextra-theme-blog or your custom theme

// Get the default MDX components
const themeComponents = getThemeComponents();

// Merge components
// export function useMDXComponents(components: React.JSX.Element) {
export function useMDXComponents(components) {
  return {
    ...themeComponents,
    ...components,
  };
}

// postcss.config.mjs
/** @type {import('postcss-load-config').Config} */
const config = {
  plugins: {
    // tailwindcss: {}, // error: 
    "@tailwindcss/postcss": {},
  },
};

export default config;

// next.config.ts 
import type { NextConfig } from "next";
import nextra from "nextra";

const nextConfig: NextConfig = {
  /* config options here */
};

const withNextra = nextra({
  // ... Other Nextra config options
});

// You can include other Next.js configuration options here, in addition to Nextra settings:
export default withNextra(nextConfig)

// src/app/globals.css
@tailwind base;
@tailwind components;
@tailwind utilities;

// package.json
{
  "name": "my-project",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "next dev --turbopack",
    "build": "next build",
    "start": "next start",
    "lint": "next lint"
  },
  "dependencies": {
    "next": "15.1.7",
    "nextra": "^4.2.10",
    "nextra-theme-docs": "^4.2.10",
    "react": "^19.0.0",
    "react-dom": "^19.0.0"
  },
  "devDependencies": {
    "@eslint/eslintrc": "^3",
    "@tailwindcss/postcss": "^4.0.6",
    "@types/node": "^20",
    "@types/react": "^19",
    "@types/react-dom": "^19",
    "eslint": "^9",
    "eslint-config-next": "15.1.7",
    "postcss": "^8",
    "tailwindcss": "^3.4.1",
    "typescript": "^5"
  }
}

// tailwind.config.ts
import type { Config } from "tailwindcss";

export default {
  content: [
    "./src/pages/**/*.{js,ts,jsx,tsx,mdx}",
    "./src/components/**/*.{js,ts,jsx,tsx,mdx}",
    "./src/app/**/*.{js,ts,jsx,tsx,mdx}",
  ],
  theme: {
    extend: {
      colors: {
        background: "var(--background)",
        foreground: "var(--foreground)",
      },
    },
  },
  plugins: [],
} satisfies Config;

Any ideas what the issue might be?

[pdsuwwz]

Hey, please try using tailwindcss v4 version and make good use of @tailwindcss/cli to help you quickly Upgrade to the corresponding architecture.

In v4 you import Tailwind using a regular CSS @import statement, not using the @tailwind directives you used in v3:

https://tailwindcss.com/docs/upgrade-guide#removed-tailwind-directives

[Adicwu]

Hey, please try using tailwindcss v4 version and make good use of @tailwindcss/cli to help you quickly Upgrade to the corresponding architecture.嘿，请尝试使用 tailwindcss v4 版本，并充分利用 @tailwindcss/cli 来帮助您快速升级到相应的架构。

In v4 you import Tailwind using a regular CSS @import statement, not using the @tailwind directives you used in v3:在 v4 中，您可以使用常规 CSS @import 语句导入 Tailwind，而不是使用 v3 中使用的 @tailwind 指令： https://tailwindcss.com/docs/upgrade-guide#removed-tailwind-directives

my component library is based on tailwindcss v3 version,
so , is there a way to use the v3 version?

[pdsuwwz]

JavaScript config files are still supported for backward compatibility, but they are no longer detected automatically in v4.
https://tailwindcss.com/docs/upgrade-guide#using-a-javascript-config-file