cardWidget.dart

...
  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: EdgeInsets.symmetric(horizontal: 10),
      child: Container(
        height: 50,
        padding: EdgeInsets.only(bottom: 20),
        decoration: new BoxDecoration(
          image: new DecorationImage(
            image: 'assets/images/card.png'),
            fit: BoxFit.cover,
          ),
        ),
        child: Center(
          child: Padding(
            padding: const EdgeInsets.symmetric(horizontal: 42.0, vertical: 18),
            child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  _buildTitle(),
                  customYMargin(35),
                  _buildName(),
                  customYMargin(40),
                  _buildExpiry()
                ]),
          ),
        ),
      ),
    );
  }
  
  ...