when i use margin ,it work fine,container is going up but its taking a lot of space on screen,there are two blue line

问题

Column(
  mainAxisAlignment: MainAxisAlignment.center,
  children: <Widget>[
    Container(
      margin: EdgeInsets.only(bottom: 400.0),
      child: Center(
        child: Padding(
          padding: EdgeInsets.symmetric(horizontal: 10.0),
          child: Text(
            _text,
            style: TextStyle(color: Colors.white),
          ),
        ),
      ),
    ),
    ...

来源：https://stackoverflow.com/questions/59777112/when-i-use-margin-it-work-fine-container-is-going-up-but-its-taking-a-lot-of-sp