Cannot change Cesium3DTileStyle by CallbackProperty

Here is my code

  // num.value is a `Number` and it can be changed by <input />
  const num = ref(60)

  const tileset = await Cesium.Cesium3DTileset.fromUrl('/building/tileset.json')
  tileset.style = new Cesium.CallbackProperty(
    () =>
      new Cesium.Cesium3DTileStyle({
        color: `color("#fff",${num.value / 100})`
      }),
    false
  )

Even the initial value does not work which make me confused.
I do not understand how it works, which may cause the issue. It will be helpful if anyone could explain how CallbackProperty works :pray:

tileset.style is not a Property, thus you cannot assign a CallbackProperty to it.

If you update num, you also have to set the style again, or at least set the color of the style.