npm scripts including node-sass and autoprefixer

package.json

{
  "name": "foo",
  "version": "1.0.0",
  "description": "foo project",
  "main": "index.js",
  "scripts": {
    "start": "npm run serve | npm run watch-css",
    "serve": "./node_modules/.bin/http-server -p 8080",
    "build-css": "./node_modules/node-sass/bin/node-sass app/sass/style.scss -o app/css/ && ./node_modules/postcss-cli/bin/postcss --use autoprefixer app/css/style.css -d app/css/",
    "watch-css": "nodemon -e scss -x 'npm run build-css'"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "autoprefixer": "6.1.2",
    "node-sass": "3.4.2",
    "postcss-cli": "2.3.2"
  },
  "devDependencies": {
    "http-server": "^0.8.5"
  }
}

@aronhoyer I got working scripts:

"build-css": "./node_modules/node-sass/bin/node-sass public/sass/index.scss -o public/css && npx ./node_modules/postcss-cli/bin/postcss public/css/index.css  --use autoprefixer -d public/css",
"watch-css": "./node_modules/nodemon/bin/nodemon.js -e scss -x 'npm run build-css'"