Space between the numbers

[desmeit]

I use a box decoration and therefore I want to have space between the numbers. Is that possible?

SlideCountdownClock(
                  duration: const Duration(minutes: 5),
                  slideDirection: SlideDirection.Up,
                  separator: ":",
                  textStyle: const TextStyle(
                    color: Colors.white,
                    fontSize: 32,
                    fontWeight: FontWeight.bold,
                    //letterSpacing: 20,
                  ),
                  shouldShowDays: false,
                  separatorTextStyle: const TextStyle(
                      fontSize: 32,
                      fontWeight: FontWeight.bold,
                      color: Colors.blue),
                  padding: const EdgeInsets.all(10),
                  decoration: BoxDecoration(
                      color: Colors.blue,
                      shape: BoxShape.rectangle,
                      borderRadius: BorderRadius.circular(10),
                      )),
                  onDone: () {
                    print("finished");
                  },