fix demo acrylic

Zhao Yuhang

2023-12-23 03c2a26820691493f5ebe86f64e0e360b0561642

 examples/mainwindow/light-style.qss

@@ -144,6 +144,10 @@
    background-color: #F3F3F3;
}

MainWindow[custom-style=true] {
    background-color: transparent;
}

QWidget#clock-widget {
    font-size: 75px;
    color: #333333;