text: #include "mainwindow.h"
  #include "ui_mainwindow.h"
  
  #include <memory>
  
  MainWindow::MainWindow(QWidget *parent)
      : QMainWindow(parent)
      , ui(new Ui::MainWindow)
  {
      ui->setupUi(this);
  }
  
  MainWindow::~MainWindow()
  {
      delete ui;
  }
  
  void MainWindow::on_pushButton_clicked()
  {
      auto palette = std::make_unique<QPalette>();
      palette->setColor(QPalette::Base, Qt::lightGray);
      palette->setColor(QPalette::Text, Qt::gray);
      ui->lineEdit_FirstName->setPalette(*palette);
      // ui->lineEdit_FirstName->setDisabled(true);
      ui->lineEdit_FirstName->setText("Grayed Out");
  }
  