update readme.md

README

@@ -13,14 +13,21 @@ http://fanruan.design/doc.html?post=0169cf558d
 
 ## 开发
 
-pnpm run dev
+`pnpm run dev`
 
 * demo: [http://localhost:3000/](http://localhost:3000/)
 * fineui: [http://localhost:9001/fineui.js](http://localhost:9001/fineui.js)
 
 ## 构建
 
-pnpm run build
+`pnpm run build`
+
+## 自定义less变量构建
+
+```
+cd ./packages/fineui
+cross-env LESS_CONFIG_PATH=your_less_config.json LESS_FILE_NAME=your_file_name pnpm --filter @fui/core webpack:css
+```
 
 ## 发布