[1666] Failed to find '~assets/styles/....css'

code url : https://github.com/shen100/golang123

npm run dev 

error:

  nuxt:build Generating files... +10ms
  nuxt:build Generating routes... +8ms
  nuxt:build Building files... +42ms
  nuxt:build Adding webpack middleware... +120ms
  build [=============       ] 65%Error: Failed to find '~assets/styles/about.css'
    in [ 
        /Users/abujj/gogit/src/golang123/website/pages,
        /Users/abujj/gogit/src/golang123/website,
        /Users/abujj/gogit/src/golang123/website,
        /Users/abujj/gogit/src/golang123/website/node_modules
    ]
    at /Users/abujj/gogit/src/golang123/website/node_modules/postcss-import/lib/resolve-id.js:48:11
    at <anonymous>
Error: Failed to find '~assets/styles/home.css'

nuxt.config.js

module.exports = {
  /*
  ** Headers of the page
  */
  head: {
    titleTemplate: '%s -',
    meta: [
      { charset: 'utf-8' },
 
    link: [
      { rel: 'icon', type: 'image/x-icon', href: '/favicon.ico' },
      { rel: 'stylesheet', href: '/styles/iview-2.0.0.css' }
    ]
  },
  css: [
    '~assets/styles/common.css'
  ],
  /*
  ** Customize the progress-bar color
  */
  loading: { color: '#80bd01' },
  build: {
    /*
    ** Run ESLINT on save
    */
    extend (config, ctx) {
      if (ctx.isClient) {
        config.module.rules.push({
          enforce: 'pre',
          test: /\.(js|vue)$/,
          loader: 'eslint-loader',
          exclude: /(node_modules)/
        })
      }
    },
    vendor: ['axios', 'iview']
  },
  plugins: [
    { src: '~plugins/iview.js', ssr: true },
    { src: '~plugins/ga.js', ssr: false }
  ]
}

env:

mac 
node -v  v8.5.0
npm -v 5.4.2
nuxt -v  r9 and r11 all error

i don't konw why error please help :)