I learn Qt. So, now I start make my mini-project and encountered in this issue – all my widgets shifting slightly right and down and my first two widgets also have a black space in the middle, why?
sorry, I don’t have Git, so I just Copy-Pasted the code.
headers:

#ifndef TOPAREACLASS_H
#define TOPAREACLASS_H

#include <QObject>
#include <QWidget>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QLabel>
#include <QPixmap>
#include <QComboBox>
#include <QLineEdit>

class topAreaClass : public QWidget
{
    Q_OBJECT
public:
    explicit topAreaClass(const QString& label,const QString& path, QWidget *parent = nullptr);

private:
    QWidget* topArea;
    QWidget* leftTopArea;

    QHBoxLayout* topHBoxLayout;
    QVBoxLayout* leftTopVBoxLayout;

    QPixmap* m_pixLabelCurrency;
    QLabel* m_currencyLabelPicture;
    QLabel* m_nameOfCurrency;
    QLineEdit* m_edit1;
};

#endif // TOPAREACLASS_H

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QVBoxLayout>
#include <QHBoxLayout>
#include <QLabel>
#include <QPixmap>
#include <QComboBox>
#include <QLineEdit>


class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
private slots:

private:
    QWidget* topArea;
    QWidget* leftTopArea;

    QHBoxLayout* topHBoxLayout;
    QVBoxLayout* leftTopVBoxLayout;

    QPixmap* m_pixLabelCurrency;
    QLabel* m_currencyLabelPicture;
    QLabel* m_nameOfCurrency;
    QLineEdit* m_edit1;
};

#endif // WIDGET_H

cpp:

#include "widget.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}

#include "topareaclass.h"

topAreaClass::topAreaClass(const QString& Label,const QString& path, QWidget *parent)
    : QWidget{parent}
{
    //topArea
    topArea = new QWidget(this);
    setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
    setFixedSize(500, 70);
    setStyleSheet("background: grey;");

    //leftTopArea
    leftTopArea = new QWidget(topArea);
    leftTopArea->setFixedSize(70, 70);
    leftTopArea->setStyleSheet("background: grey;");
    leftTopVBoxLayout = new QVBoxLayout(leftTopArea);
    leftTopVBoxLayout->setContentsMargins(5,5,5,5);

    //Flag
    m_pixLabelCurrency = new QPixmap(path);
    m_currencyLabelPicture = new QLabel();
    m_currencyLabelPicture->setPixmap(m_pixLabelCurrency->scaled(60,30, Qt::KeepAspectRatio));
    m_currencyLabelPicture->setAlignment(Qt::AlignCenter);

    //Usd
    m_nameOfCurrency = new QLabel(Label);
    m_nameOfCurrency->setAlignment(Qt::AlignCenter);


    leftTopVBoxLayout->addWidget(m_currencyLabelPicture);
    leftTopVBoxLayout->addWidget(m_nameOfCurrency);

    //edit1 (topRight)
    m_edit1 = new QLineEdit("100000");
    m_edit1->setAlignment(Qt::AlignRight | Qt::AlignVCenter);
    m_edit1->setStyleSheet("border: none;"
                           "font-size: 35px;"
                           "margin-right: 10px;");
    m_edit1->setFixedHeight(70);

    //QHBoxLayout

    topHBoxLayout = new QHBoxLayout(this);
    topHBoxLayout->setContentsMargins(0,0,0,0);

    topHBoxLayout->addWidget(leftTopArea);
    topHBoxLayout->addStretch();
    topHBoxLayout->addWidget(m_edit1);
}

#include "widget.h"
#include "topareaclass.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
    setFixedSize(500,700);
    setStyleSheet("background: black;");
    setWindowTitle("Currency Convertor");

    QVBoxLayout* mainLayout = new QVBoxLayout(this);

    topAreaClass* top1 = new topAreaClass("USD", ":/new/prefix1/build/usa.png");
    topAreaClass* top2 = new topAreaClass("UAH", ":/new/prefix1/build/uah.png");

    mainLayout->addWidget(top1);
    mainLayout->addWidget(top2);
    mainLayout->addStretch();


}

Widget::~Widget() {}

how can I fix it? So there isnt any space around widgets?