Tailwind Standalone CLI fails building with --postcss option

[seyeong]

What version of Tailwind CSS are you using?

For example: v14.3.0

What build tool (or framework if it abstracts the build tool) are you using?

For example: N/A

What version of Node.js are you using?

v14.3.0

What browser are you using?

For example: N/A

What operating system are you using?

For example: ubuntu

Reproduction URL
N/A

Describe your issue

build command fails with Loading PostCSS Plugin failed: Cannot find module 'tailwindcss' error.

➜  ~ mkdir test
➜  ~ cd test 
➜  test wget https://github.com/tailwindlabs/tailwindcss/releases/download/v3.1.4/tailwindcss-linux-x64
➜  test chmod 755 tailwindcss-linux-x64 
➜  test ./tailwindcss-linux-x64 init --full --postcss

Created Tailwind CSS config file: tailwind.config.js
Created PostCSS config file: postcss.config.js

➜  test ./tailwindcss-linux-x64 build --postcss  

warn - The `content` option in your Tailwind CSS configuration is missing or empty.
warn - Configure your content sources or your generated CSS will be missing styles.
warn - https://tailwindcss.com/docs/content-configuration
/snapshot/tailwindcss/node_modules/postcss-load-config/src/plugins.js:28
    throw new Error(`Loading PostCSS Plugin failed: ${err.message}\n\n(@${file})`)
          ^

Error: Loading PostCSS Plugin failed: Cannot find module 'tailwindcss'
Require stack:
- /home/ubuntu/test/postcss.config.js
1) If you want to compile the package/file into executable, please pay attention to compilation warnings and specify a literal in 'require' call. 2) If you don't want to compile the package/file into executable and want to 'require' it from filesystem (likely plugin), specify an absolute path in 'require' call using process.cwd() or process.execPath.

(@/home/ubuntu/test/postcss.config.js)
    at load (/snapshot/tailwindcss/node_modules/postcss-load-config/src/plugins.js:28:11)
    at /snapshot/tailwindcss/node_modules/postcss-load-config/src/plugins.js:53:16
    at Array.map (<anonymous>)
    at plugins (/snapshot/tailwindcss/node_modules/postcss-load-config/src/plugins.js:52:8)
    at processResult (/snapshot/tailwindcss/node_modules/postcss-load-config/src/index.js:37:14)
    at /snapshot/tailwindcss/node_modules/postcss-load-config/src/index.js:151:14
    at async loadPostCssPlugins (/snapshot/tailwindcss/lib/cli.js:412:16)
    at async buildOnce (/snapshot/tailwindcss/lib/cli.js:543:78)

[thecrypticace]

Hey, thanks for reporting this one! I've fixed the issue and the fix will go out when we release v3.1.5 this week. As a workaround until it's released you can remove tailwindcss and autoprefixer from the postcss config and they'll be injected automatically in the current standalone CLI. You just won't have control over their placement.