@override
  Widget build(BuildContext context) {
    return Form(
      child: Column(
        mainAxisSize: MainAxisSize.min,
        children: [
          LinearProgressIndicator(value: _formProgress),
          Text('Sign up', style: Theme.of(context).textTheme.headlineMedium),
          Padding(
            padding: const EdgeInsets.all(8.0),
            child: TextFormField(
              controller: _firstNameTextController,
              decoration: const InputDecoration(hintText: 'First name'),
            ),
          ),
          Padding(
            padding: const EdgeInsets.all(8.0),
            child: TextFormField(
              controller: _lastNameTextController,