I figured out that the css preprocessor is not really a thread.
I was using this great tool: https://www.npmjs.com/package/s2sconvert
Now my build can handle both SASS and Stylus

Unfortunately Quasar wont be our choice as it turned out that it is a kind of fullstack spa, and i need a very specific own made build, vue-cli is not an option for us.
But you did a great work, I wish you much success!

Hey thanks for replay
Of course i can use SASS and Quasar - no doubt, but iam looking for a GUI Framework for existing Projects written with SASS and now i have to make a descision. I can replace SASS with Stylus in my projects or replace Stylus in Quasar with SASS - i dont like both options
I understand your decision as you explained it.
Didnt ever heard of Stylus nowadays it doesent seem to be a thread. If its the smarter preprocessor, maybe it failed because of the inappropriate website it has.

Hello,

TL;DR
we have a couple of running websites, the front-end is maintained by gulp/sass/jquery/materialize-css, the core is .NET based. Atm, i want to pass as much view jobs from jQuery to Vue. By doing this i think about replacing the UI-framework with Quasar. I choose Vue because of its components and iam excited to get additional advantage if the UI-framework makes as well use of them.
Unfortunately after a some hours of testing, i realize that we cant use Quasar because the embeding process might be too time consuming.

You are using the exotic css-preprocessor stylus, why this?!? I wasnt able to figure out any advantages by using this instead of SASS and migrating all our SASS universe might not be an option. We got booted because of this decision