styles.qss

QWidget{
    background-color: #444444;
}

QLabel {
    color: white;
    font-size: 12pt;
}

QLineEdit{
    color: white;
    background-color: #2A2A2A;
    border: 6px solid #2A2A2A;
    border-radius: 6px;
}

QPushButton {
    color: white;
    background-color: #5B5B5B;
    font-size: 10pt;
    border: 6px solid #5B5B5B;
    border-radius: 6px;
}

QPushButton:pressed {
    background-color: #2A2A2A;
    border: 6px solid #2A2A2A;
    border-radius: 6px;
}

QPushButton:checked {
    background-color: #2A2A2A;
    border: 6px solid #2A2A2A;
    border-radius: 6px;
}

QComboBox{
    color: white;
    background-color: #2A2A2A;
    border: 6px solid #2A2A2A;
    border-radius: 6px;
}

QAbstractItemView { color: white; }

QSpinBox{
    color: white;
    background-color: #2A2A2A;
    border: 6px solid #2A2A2A;
    border-radius: 6px;
}