DFTFringe looks terrible if a windows 11 machine has dark mode set.
AI says if you do the following you can change the mode.
So perhaps add a setting in DFTFringe that enables the mode.
Here is the code to force it at startup.
#include <QApplication>
#include <QProcessEnvironment>
int main(int argc, char *argv[]) {
QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
env.insert("QT_QPA_PLATFORM", "windows:darkmode=0"); // Force light mode
QProcessEnvironment::setSystemEnvironment(env);
QApplication app(argc, argv);
// ... rest of your application code
return app.exec();
}