HarmonyOS bindContentCover绑定自定义弹窗如何修改里面组件样式？

class Tmp {  
  selectIndex: number = -1  
  reasonList:RefundReason[] = []  
  clickAction = (index:number) => {}  
}  
export class RefundReason {  
  reason:string = ''  
}  
  
export const refundReasonArray:RefundReason[] = [  
  { reason:'1111111111'},  
  { reason:'22222222'},  
  { reason:'3333333'},  
  { reason:'4444444'},  
  { reason:'5555555'},  
]  
@Entry  
@Component  
export default struct MyFollowReporterPage{  
  @State isShow:boolean = true  
  @State selectIndex:number = -1  
  @State refundReasonArray:RefundReason[] = refundReasonArray  
  ListItemClick(index:number) {  
    this.selectIndex = index  
  }  
  build(){  
    Column()  
      .bindContentCover(this.isShow,  
        KsResignAccountBuilder({  
          reasonList:this.refundReasonArray,  
          selectIndex:this.selectIndex,  
          clickAction:(index) => {  
            this.ListItemClick(index)  
          }  
        })  
      )  
  }  
}  
  
@Builder  
function KsResignAccountBuilder(params:Tmp) {  
  Column() {  
    List({ space: 0, initialIndex: 0 }) {  
      ForEach(params.reasonList, (item: RefundReason, index: number) => {  
        ListItem() {  
          Flex({  
            direction: FlexDirection.Row,  
            alignItems: ItemAlign.Center,  
            justifyContent: FlexAlign.SpaceBetween  
          }) {  
            Text(item.reason)  
              .fontColor(params.selectIndex == index ? Color.Red : Color.Black)  
              .fontSize(15)  
          }  
        }.height(50).onClick(() => {  
          params.clickAction(index)  
        })  
      }, (item: RefundReason) => JSON.stringify(item))  
    }  
  }.backgroundColor(Color.Gray).margin({top:100})  
}