Is it possible to make changes to the input file (.sass, etc.) when changing the output file (.сss)?

Question

css

Or, even like this: there are several css files that are concatenated into one.
Or even, let's say, if no mqpackers, autoprefixers and other tinsel are used, but files are simply stupidly glued into one.
Three options where synchronization is equally needed (or something) between input and output files. You need at least one solution, but best of all - the very first one - the one in the title. I will be grateful for the answer.
PS If it's interesting, then the reason for this need is not unreasonable, but very important and has no alternatives.

Answer 1

livestyle.io - check out livestyle, maybe this is what you need

Answer 2

probably possible. but there is no point. Even the same autoprefixer if you use. And you need to use it .. So after it, there will already be more lines in the output file. And it will already be unrealistic to work with the source code through ready-made files. The files will be different. See what your need is. If in debug. Then use soursemap. This simplifies debugging.
And yes, as if in sass there is & a link to the parent element and mixins, etc.) so think about how realistic it is to change sass through css