BareBone.dart

import 'package:flutter/material.dart';

class InputPage extends StatefulWidget {
  @override
  _InputPageState createState() => _InputPageState();
}

class _InputPageState extends State<InputPage> {
  Container dummy = Container(
    margin: EdgeInsets.all(12),
    decoration: BoxDecoration(

        color: Color(0xFF1D1F31),
        borderRadius: BorderRadius.all(Radius.circular(12),),),
  );

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('BMI CALCULATOR'),
        centerTitle: true,
      ),
      body: Column(
        children: <Widget>[
          Expanded(
            child: Row(
              children: <Widget>[
                Expanded(
                  child: Container(
                    margin: EdgeInsets.all(12),
                    decoration: BoxDecoration(
                      color: Color(0xFF1D1F31),
                      borderRadius: BorderRadius.all(Radius.circular(12),),),
                  ),
                ),
                Expanded(
                  child: Container(
                    margin: EdgeInsets.all(12),
                    decoration: BoxDecoration(
                      color: Color(0xFF1D1F31),
                      borderRadius: BorderRadius.all(Radius.circular(12),),),
                  ),
                )
              ],
            ),
          ),
          Expanded(
            child: Container(
              margin: EdgeInsets.all(12),
              decoration: BoxDecoration(
                color: Color(0xFF1D1F31),
                borderRadius: BorderRadius.all(Radius.circular(12),),),
            ),
          ),
          Expanded(
            child: Row(
              children: <Widget>[
                Expanded(
                  child: Container(
                    margin: EdgeInsets.all(12),
                    decoration: BoxDecoration(
                      color: Color(0xFF1D1F31),
                      borderRadius: BorderRadius.all(Radius.circular(12),),),
                  ),
                ),
                Expanded(
                  child: Container(
                    margin: EdgeInsets.all(12),
                    decoration: BoxDecoration(
                      color: Color(0xFF1D1F31),
                      borderRadius: BorderRadius.all(Radius.circular(12),),),
                  ),
                )
              ],
            ),
          ),
        ],
      ),
    );
  }
}