QT StyleSheet Theme for entire application using attribute selectors - c++

Question

Background:
I have a Qt application consisting of multiple dialogs and windows. I am trying to condense all styles into a single stylesheet which I want to load in my main.cpp with the aim of it being applied to my whole application (as I understand one should do). The application should not change styles from this point onwards.
I want to do this as styles can get mixed up, etc if one does this or something simliar for each widget in the QtCreator designer.
Problem:
I will explain a specific problem I face with an example from my application.
I have a couple of variations of simple dialogs, QLabel title, QLabel message (sometimes a QLabel hint), and either a single 'ok' QPushButton or 2 QPushButtons 'positive' & 'negative'.
For my theme, I would like to set styles for specific buttons, labels, etc which I got from here.
Example CSS:
QPushButton {
font-size: 10pt
color: #111
}
QPushButton[objectName="btnPostive"][objectName="btnProceed"] {
font-size: 1pt
color: #ccc
}
QLabel {
font-size: 9pt
color: #111
}
QLabel[objectName="lblTitle"] {
font-size: 9pt
color: #111
}
Please note, the [objectName="btnPostive"][objectName="btnProceed"] is intended to apply the style to buttons with the objectName's btnPostive and btnProceed however, it does not.
Is what I intend doing considered best practice, and a sub question (preferred example too) applying the same style to a select group of widgets, how should one best this.

Answer 1

If you want to control the applied stylesheet based on the object name, you can use the ID Selector QPushButton#objectName, see the full documentation. You separate multiple objects with the same stylesheet with a ,
Your stylesheet should then be this. Please note that you also need a ; at the end of each line.
QPushButton {
font-size: 10pt;
color: #111;
}
QPushButton#btnPositive, QPushButton#btnProceed {
font-size: 1pt;
color: #ccc;
}
QLabel {
font-size: 9pt;
color: #111;
}
QLabel#lblTitle {
font-size: 9pt;
color: #00f;
}