我想给予下拉按钮和下拉菜单的边框，如下图所示沿着高度itemHeight为21px，鼠标悬停和键盘上的向上或向下键的下拉菜单项的一些背景颜色：

以下是我到目前为止所做的尝试：

var genderList = [
    'Female',
    'Male',
    'Other',
  ];

  String? selection;

  final border = const OutlineInputBorder(
    borderSide: BorderSide(
      width: 1,
      color: Color(0xFF00AFEF),
    ),
    borderRadius: BorderRadius.all(Radius.circular(7)),
  );
...
                    SizedBox(
                      height: 38.h,
                      // color: Colors.blue,
                      child: InputDecorator(
                        decoration: InputDecoration(
                          contentPadding: EdgeInsets.zero,
                          border: border,
                          enabledBorder: border,
                        ),
                        child: DropdownButtonHideUnderline(
                          child: DropdownButton(
                            isExpanded: true,
                            hint: Align(
                              alignment: Alignment.centerLeft,
                              child: Padding(
                                padding: EdgeInsets.symmetric(horizontal: 13.w),
                                child: const Text(
                                  'Gender',
                                  style: TextStyle(
                                    fontSize: 14,
                                    color: Color(0xFF606060),
                                  ),
                                ),
                              ),
                            ),
                            value: selection,
                            icon: Container(
                              margin: EdgeInsets.symmetric(horizontal: 13.w),
                              height: 10.r,
                              width: 16.r,
                              alignment: Alignment.center,
                              child: SvgPicture.asset(
                                AppIcons.arrowDown,
                              ),
                            ),
                            onChanged: (String? val) {
                              setState(() => selection = val);
                            },
                            items: genderList.map((option) {
                              return DropdownMenuItem(
                                value: option,
                                child: Container(
                                  width: double.infinity,
                                  height: 21.h,
                                  alignment: Alignment.center,
                                  decoration: BoxDecoration(
                                      color: Color(0xFFCBF1FF),
                                      border: Border.all(
                                          color: Color(0xFF00AFEF), width: 1)),
                                  child: Text(
                                    option,
                                    style: TextStyle(
                                      fontSize: 12,
                                      color: Color(0xFF606060),
                                    ),
                                  ),
                                ),
                              );
                            }).toList(),
                            selectedItemBuilder: (con) {
                              return genderList.map((val) {
                                return Align(
                                  alignment: Alignment.centerLeft,
                                  child: Padding(
                                    padding: EdgeInsets.only(left: 13.w),
                                    child: Text(
                                      val,
                                      textAlign: TextAlign.center,
                                      style: const TextStyle(
                                        fontSize: 14,
                                        color: Color(0xFF606060),
                                      ),
                                    ),
                                  ),
                                );
                              }).toList();
                            },
                          ),
                        ),
                      ),
                    );

我得到的，
下拉按钮：

下拉菜单：

我怎样才能得到想要的设计？