Does anyone can systematically about the relationship and online is reproduced to distribute to all of that shape, are less than point,

There are several situations:
1. The main function, loading QSS file directly,
2. Within the program calls for a control yourself write setstylesheet,
3. The change in their program qpalette,
4. The UI files inside change some features, such as the font size,

You will find the above four kinds of things at the same time a few dry, will be very wonderful to cover each other, failure of each other, but may not have all failed, anyhow is not expected, you very egg pain, but you want to change flexibly particular moment on the basis of the original part features, or back to the original, is the meaning of the toggle, but you may don't know what the original sample within the program, because QSS is loaded in,

I think should be like this:
Loading QSS is the boss, but just moment, if behind program changed, should give it a variable, or UI file has changed too, and then can be fixed in API change back,