🤔对比漏斗图或者分面漏斗图的顶部的compareField的样式如何设置呢？

### 🐛 Question description [Please make everyone to understand it]

### 💻 Link to minimal reproduction

Please provide a link by forking these links [g2plot](https://codesandbox.io/s/g2plot-reproduction-template-gyej1) or GitHub repo. What is a minimal reproduction, and why is it required?

### 🏞 Expected result

### 🚑 Any additional [like screenshots]

* **G2Plot Version**:
* **Platform**:

No file, test, entry point, minimal reproduction, expected result, version, or platform is provided. First clarify the desired compareField styling for comparison or faceted funnel charts and request a minimal reproduction. Done is a concrete, agreed styling requirement with a reproducible example and an identified implementation location.

Written by the indexing model from the issue text.