message: docs: update theme.en-US.md
diff: @@ -78,11 +78,33 @@ module.exports = {
  'border-color': '#eee'
  // or override with less file
  'hack': `true; @import "your-less-file-path.less";`
  - }
  - }
  - }
  - ]
  - }
  - ]
  + },
  + },
  + },
  + ],
  + },
  + ],
  };
  ```
  +
  +If you build a project by vue-cli,it can be configured in `vue.config.js`:
  +
  +```js
  +// vue.config.js
  +module.exports = {
  + css: {
  + loaderOptions: {
  + less: {
  + modifyVars: {
  + // overide with less vars
  + 'text-color': '#111',
  + 'border-color': '#eee',
  + // or override with less file
  + hack: `true; @import "your-less-file-path.less";`,
  + },
  + },
  + },
  + },
  +};
  +```
  +
  