make rounded ConfigurableExpansionTile

[yogithesymbian]

                              decoration: BoxDecoration(
                                // shape: BoxShape.circle,
                                borderRadius: BorderRadius.all(
                                  Radius.circular(32.0),
                                ),
                                color: Colors.black,
                              ),

i have tried and added container instead of header or the widget ConfigurableExpansionTile outside but the output is not full rounded ...

if i added outside the widget , thats container height would ++ height, i just want to decoration of header , and body is still transparent

my code tried

Expanded(
                      flex: 0,
                      child: Container(
                        decoration: BoxDecoration(
                          borderRadius: BorderRadius.all(
                            Radius.circular(32.0),
                          ),
                          color: kColorLightBlue,
                        ),
                        margin: EdgeInsets.all(16.0),
                        child: ConfigurableExpansionTile(
                          borderColorStart: Colors.transparent,
                          borderColorEnd: Colors.transparent,
                          bottomBorderOn: true,
                          topBorderOn: true,
                          animatedWidgetFollowingHeader: Icon(
                            Icons.expand_more,
                            color: Colors.white,
                          ),
                          headerExpanded: Flexible(
                            child: Row(
                              children: [
                                Container(
                                  padding: EdgeInsets.all(8.0),
                                  decoration: BoxDecoration(
                                    shape: BoxShape.circle,
                                  ),
                                  child: Text(
                                    "HEADER",
                                    style: kTitleText.copyWith(
                                      fontSize: 14.0,
                                    ),
                                  ),
                                ),
                              ],
                            ),
                          ),
                          header: Flexible(
                            child: Row(
                              children: [
                                Container(
                                  padding: EdgeInsets.all(8.0),
                                  child: Text(
                                    "HEADER",
                                    style: kTitleText.copyWith(
                                      fontSize: 14.0,
                                    ),
                                  ),
                                ),
                              ],
                            ),
                          ),
                          // headerBackgroundColorStart: kColorLightBlue,
                          expandedBackgroundColor: Colors.transparent,
                          // headerBackgroundColorEnd: kColorLightBlue,
                          children: [
                            Row(
                              children: [
                                Text("CHILD 1"),
                              ],
                            ),
                            Row(
                              children: [
                                Text("CHILD 2"),
                              ],
                            )
                          ],
                        ),
                      ),
                    ),