QFD2/QFluentWidgets/qss/light/spin_box.qss

SpinBox, DoubleSpinBox, DateEdit, DateTimeEdit, TimeEdit {
    color: black;
    background-color: white;
    border: 1px solid rgba(0, 0, 0, 13);
    border-bottom: 1px solid rgba(0, 0, 0, 100);
    border-radius: 5px;
    font: 14px "Segoe UI", "Microsoft YaHei";
    padding: 0px 80px 0 10px;
    selection-background-color: --ThemeColorLight1;
}

SpinBox:hover,
DoubleSpinBox:hover,
DateEdit:hover,
DateTimeEdit:hover,
TimeEdit:hover {
    background-color: rgb(252, 252, 252);
    border: 1px solid rgba(0, 0, 0, 13);
    border-bottom: 1px solid rgba(0, 0, 0, 100);
}

SpinBox:!focus,
DoubleSpinBox:!focus,
DateEdit:!focus,
DateTimeEdit:!focus,
TimeEdit:!focus {
    background-color: white;
    border-bottom: 1px solid rgba(0, 0, 0, 100);
}

SpinBox:focus,
DoubleSpinBox:focus,
DateEdit:focus,
DateTimeEdit:focus,
TimeEdit:focus {
    border-bottom: 1px solid rgba(0, 0, 0, 13);
    background-color: white;
}

SpinBox:disabled,
DoubleSpinBox:disabled,
DateEdit:disabled,
DateTimeEdit:disabled,
TimeEdit:disabled {
    color: rgba(0, 0, 0, 150);
    background-color: rgb(252, 252, 252);
    border: 1px solid rgb(237, 237, 237);
}

SpinButton {
    background-color: transparent;
    border-radius: 4px;
    margin: 0;
}

SpinButton:hover {
    background-color: rgba(0, 0, 0, 9);
}

SpinButton:pressed {
    background-color: rgba(0, 0, 0, 6);
}