fix unwanted title bar when special effect is enabled

Zhao Yuhang

2025-02-08 6f4ab6474fa81556b1d90f6f87f8322282d054db

 examples/mainwindow/mainwindow.qrc

@@ -1,5 +1,6 @@
<RCC>
    <qresource prefix="/">
        <file>dark-style.qss</file>
        <file>light-style.qss</file>
    </qresource>
</RCC>