我尝试将其部署到Heroku，这是我尝试将其推入Heroku时收到的错误。这里是我目前遇到的错误。我看到我当前遇到的错误涉及顺风，但是我不确定该如何处理。

       Running heroku-postbuild
       
       > ecommerce@1.0.0 heroku-postbuild /tmp/build_1c2bd436
       > NPM_CONFIG_PRODUCTION=false npm install --prefix client && npm run build --prefix client
       
       
       > core-js@2.6.11 postinstall /tmp/build_1c2bd436/client/node_modules/babel-runtime/node_modules/core-js
       > node -e "try{require('./postinstall')}catch(e){}"
       
       
       > core-js@3.6.5 postinstall /tmp/build_1c2bd436/client/node_modules/core-js
       > node -e "try{require('./postinstall')}catch(e){}"
       
       
       > core-js-pure@3.6.5 postinstall /tmp/build_1c2bd436/client/node_modules/core-js-pure
       > node -e "try{require('./postinstall')}catch(e){}"
       
       added 1657 packages from 798 contributors and audited 1740 packages in 45.079s
       
       68 packages are looking for funding
         run `npm fund` for details
       
       found 0 vulnerabilities
       
       
       > client@0.1.0 build /tmp/build_1c2bd436/client
       > npm run build:css && react-scripts build
       
       
       > client@0.1.0 build:css /tmp/build_1c2bd436/client
       > postcss src/Assests/tailwind.css -o src/Assests/main.css
       
sh: 1: postcss: not found
npm ERR! code ELIFECYCLE
npm ERR! syscall spawn
npm ERR! file sh
npm ERR! errno ENOENT
npm ERR! client@0.1.0 build:css: `postcss src/Assests/tailwind.css -o src/Assests/main.css`
npm ERR! spawn ENOENT
npm ERR! 
npm ERR! Failed at the client@0.1.0 build:css script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR!     /tmp/npmcache.tYOmN/_logs/2020-09-25T00_53_01_969Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! client@0.1.0 build: `npm run build:css && react-scripts build`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the client@0.1.0 build script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR!     /tmp/npmcache.tYOmN/_logs/2020-09-25T00_53_01_990Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! ecommerce@1.0.0 heroku-postbuild: `NPM_CONFIG_PRODUCTION=false npm install --prefix client && npm run build --prefix client`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the ecommerce@1.0.0 heroku-postbuild script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR!     /tmp/npmcache.tYOmN/_logs/2020-09-25T00_53_02_014Z-debug.log
-----> Build failed ```

这是我在客户端的package.json

{
  "name": "client","version": "0.1.0","private": true,"dependencies": {
    "@testing-library/jest-dom": "^4.2.4","@testing-library/react": "^9.5.0","@testing-library/user-event": "^7.2.1","axios": "^0.20.0","http-proxy-middleware": "^1.0.5","react": "^16.13.1","react-dom": "^16.13.1","react-redux": "^7.2.1","react-router-dom": "^5.2.0","react-scripts": "3.4.3","react-stripe-checkout": "^2.6.3","redux": "^4.0.5","redux-thunk": "^2.3.0"
  },"scripts": {
    "start": "npm run watch:css && react-scripts start","build": "npm run build:css && react-scripts build","test": "react-scripts test","eject": "react-scripts eject","build:css": "postcss src/Assests/tailwind.css -o src/Assests/main.css","watch:css": "postcss src/Assests/tailwind.css -o src/Assests/main.css"
  },"eslintConfig": {
    "extends": "react-app"
  },"browserslist": {
    "production": [
      ">0.2%","not dead","not op_mini all"
    ],"development": [
      "last 1 chrome version","last 1 firefox version","last 1 safari version"
    ]
  },"devDependencies": {
    "autoprefixer": "^9.8.6","i": "^0.3.6","postcss-cli": "^7.1.2","tailwindcss": "^1.8.9"
  }
}

这是服务器端的package.json。

{
  "name": "ecommerce","version": "1.0.0","description": "","main": "index.js","engines": {
    "node": "14.4.0","npm": "6.14.8"
  },"scripts": {
    "server": "nodemon server.js","client": "npm run start --prefix client","dev": "concurrently \"npm run server\" \"npm run client\"","heroku-postbuild": "NPM_CONFIG_PRODUCTION=false npm install --prefix client && npm run build --prefix client"
  },"keywords": [],"author": "","license": "ISC","dependencies": {
    "body-parser": "^1.19.0","concurrently": "^5.3.0","cookie-session": "^1.4.0","express": "^4.17.1","mongoose": "^5.10.7","nodemon": "^2.0.4","passport": "^0.4.1","passport-google-oauth20": "^2.0.0","stripe": "^8.100.0"
  }
}

有什么建议吗？ 谢谢！