File fix-dark-theme.patch of Package khelpcenter

diff -ruNp a/mainwindow.cpp b/mainwindow.cpp
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -33,7 +33,11 @@
 #include <QTextDocument>
 #include <QTextEdit>
 #include <QVBoxLayout>
-
+#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
+#include <QApplication>
+#include <QStyleHints>
+#include <QWebEngineSettings>
+#endif
 #include <KActionCollection>
 #include <KActionMenu>
 #include <KBookmarkManager>
@@ -147,6 +151,11 @@ MainWindow::MainWindow()
     statusBarMessage(i18n("Ready"));
     enableCopyTextAction();
 
+#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
+    applyContentColorScheme();
+    mDoc->page()->setBackgroundColor(Qt::transparent); // Prevent displaying a white page at startup
+#endif
+
     readConfig();
 }
 
@@ -440,6 +449,22 @@ void MainWindow::slotPrintPreview()
     printDoc->printPreview();
 }
 
+#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
+void MainWindow::applyContentColorScheme()
+{
+    auto colorScheme = QApplication::styleHints()->colorScheme();
+    mDoc->page()->settings()->setAttribute(QWebEngineSettings::ForceDarkMode, colorScheme == Qt::ColorScheme::Dark);
+}
+
+void MainWindow::changeEvent(QEvent *e)
+{
+    if (e->type() == QEvent::StyleChange) {
+        applyContentColorScheme();
+    }
+    QWidget::changeEvent(e);
+}
+#endif
+
 #include "moc_mainwindow.cpp"
 
 // vim:ts=2:sw=2:et
diff -ruNp a/mainwindow.h b/mainwindow.h
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -79,6 +79,9 @@ protected:
 
     void readConfig();
     void writeConfig();
+#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
+    void changeEvent(QEvent *e) override;
+#endif
 
 protected Q_SLOTS:
     void enableLastSearchAction();
@@ -103,6 +106,9 @@ private Q_SLOTS:
 
 private:
     void updateFontScaleActions();
+#if QT_VERSION >= QT_VERSION_CHECK(6, 7, 0)
+    void applyContentColorScheme();
+#endif
 
     QSplitter *mSplitter = nullptr;
     ViewContainer *mViewContainer = nullptr;