- [ ] I have searched the [issues](https://github.com/vueComponent/ant-design-vue/issues) of this repository and believe that this is not a duplicate. ### What problem does this feature solve? 之前使用的2.1.2版本边框基本都是#EEEEEE,想问下加深颜色是出于什么Y原因呢,现在升级后整体看着有点突兀 ### What does the proposed API look like? -- <!-- generated by issue-helper. DO NOT REMOVE -->