@Pinegrow_User thanks for such detailed proposal 
That’s indeed something we’re working towards, and as you noticed, a lot of changes in Pinegrow 3 and 4 have been laying the groundwork for making such features possible.
A couple of issues are still open:
- Where to store the manipulated CSS prop: into style attribute, a selected CSS rule…, without creating a mess.
- How to handle situations where changing the width, for example, will have no effect because a higher priority CSS rule is setting the value, or, if max-width is set somewhere.
It’s easy to make a simple on-page controls that work with style attribute. But, look at Macaw, it had powerful GUI manipulation tools, but users were not happy with the code output and with Scarlet it seemed they abandoned that approach and instead wanted to do something quite similar to Pinegrow.
Visual approach usually doesn’t lead to a well structured code and maintainable projects. I think, it can be pulled off in an usable way, but designing this process still requires some fine tunning.