message: simplify css.js
diff: // @preval
  -const {join} = require('path')
  -const {readFileSync} = require('fs')
  -module.exports = readFileSync(join(process.cwd(), 'dist/css/build.css'), 'utf8')
  +const path = require('path')
  +const fs = require('fs')
  +module.exports = fs.readFileSync(path.join(__dirname, '../dist/css/build.css'), 'utf8')
  