I think the mix was done precisely in order not to touch the css values during updates, it's already a very good thing.
I know that everything is not editable via the mix, but if you want to avoid starting again every time, as far as possible it is better to stay with the original code.
The inconvenience is all the more important as the updates are frequent for the moment.
If you have changes to make outside of the mix values, then you'll want to do them later when updates are less frequent.