Vue components css background-image path error : <p>output</p>

<pre><code>    output: {
        path: config.build.assetsRoot,
        publicPath: process.env.NODE_ENV === 'production' ? 
        config.build.assetsPublicPath : config.dev.assetsPublicPath,
        filename: '[name].js'
    }
</code></pre>

<p>base</p>

<pre><code>  build: {
    env: require('./prod.env'),
    index: path.resolve(__dirname, '../dist/index.html'),
    assetsRoot: path.resolve(__dirname, '../dist'),
    assetsSubDirectory: 'static',
    assetsPublicPath: './',
    productionSourceMap: false,
    productionGzip: false,
    productionGzipExtensions: ['js', 'css']
  },
</code></pre>

<p>after build,the index pages work normal, css background-image path like this </p>

<pre><code>background: url(./static/img/bg_certificate.c5cad1e.png) no-repeat 50%;
</code></pre>

<p>but the component css background-image path error, like this </p>

<pre><code>background: url(static/img/btn_my.b9186cc.png) no-repeat 50%;
</code></pre>

<p>It's look like the path lose "./",</p>
