Frankly, using Bootstrap from source is really easy, and tends to be my default path... I copy the bootstrap.less/scss as well as variables.scss to my project, update all the refs to the node_modules path(s), with the local variables... this way I can update said variables. I also create a local utils that includes the modules one... I'll add the local global styles to the lookup in webpack, and I'm off.

It's really nice, and allows me to comment out the bits I don't want/need and customize the few things I want changed (noto/consolas for fonts) and reuse the variables/fonts where needed.

Foundation, iirc originally required ruby, when I already was using node/npm for a lot of things... the better sass support via npm came later.