fluent_widgets_pyside6/app/resource/qss/dark/system_interface.qss

SettingInterface, #scrollWidget {
    background-color: transparent;
}

QScrollArea {
    border: none;
    background-color: transparent;
}


/* 标签 */
QLabel#label3 {
    font: 33px 'Microsoft YaHei Light';
    background-color: transparent;
    color: red;
}

QLabel#label5 {
    font: 33px 'Microsoft YaHei Light';
    background-color: transparent;
    color: red;
}