Import SCSS relative paths


When I import a scss file into another, all relative paths are not working
the problem is with webpack I believe, any suggestions?

More info:
I need to use some NPM modules in my theme, and I am not sure what is the right way to do this
So I just installed those packages in MyTheme/src/Resources/app/storefront/src/node_modules
And in MyTheme/src/Resources/app/storefront/src/scss/base.scss I import my styles with @import ‚…/node_modules/mymodule/style.scss‘;
But style.scss has some relative paths to other files, and those paths can’t be resolved by the compiler

I’m missing something?
Or is does it not mean to be done like this?

Also, why is there not documentation on Shopware on how to work NPM or WebPack?