[solved] if Cesium supports colored CityGML models

[update] After deleting ‘theme’ tag of ‘appearance’, it can work correctly. Now the color of citygml model can be shown in Cesium by uploading from cesium ion
reference from this post: CityGML has no color after uploading to Cesium Ion - #7 by Dave_Braig
==========================segment line==================================
When I upload a 3D model in CityGML format in Cesium ion, it can correctly load and display the CityGML model with image textures, but it seems that it does not support displaying the CityGML model with colors specified in ‘appearance’ tag. For example, I have a CityGML model file, and define the following colors in the appearance tag:
app:appearance
app:Appearance
app:surfaceDataMember
<app:X3DMaterial gml:id=“blue_texture”>
app:diffuseColor0.0 0.97647 0.102</app:diffuseColor>
app:transparency0.0</app:transparency>
app:target#polygon_face_0</app:target>
</app:X3DMaterial>
</app:surfaceDataMember>
</app:Appearance>
</app:appearance>
This model can display colors correctly in other software (such as FME). However, after uploading to Cesium ion, the model is white (the default model without color).
I would like to know if Cesium supports displaying CityGML models that have colors defined in this way? If not, how should I develop JavaScript code to correctly display CityGML models with colors defined in Cesium? Is there any plan to support this in the future?