As someone who has gone great lengths to improve this by creating a smaller bootstrap [1], I have to say that in the end of the day it will probably not matter. CSS is hardly the bottleneck and the same time spent optimizing it would probably be better spent:
- Optimizing your images.
- Concatenating+minimizing+gzip the JS and CSS.
- Optimizing Javascript.
Likely in order; mileage might vary. If those 3 are already in place, then it might make some difference to optimize the CSS.
First meassure what you actually want to improve (it is not page size per se, it is loading time). Then make sure that you optimize it and not something else.
- Optimizing your images.
- Concatenating+minimizing+gzip the JS and CSS.
- Optimizing Javascript.
Likely in order; mileage might vary. If those 3 are already in place, then it might make some difference to optimize the CSS.
First meassure what you actually want to improve (it is not page size per se, it is loading time). Then make sure that you optimize it and not something else.
[1] https://picnicss.com/