Yuh, my first guess was webpack messing with my load order, but I'm not sure. I feel there're some syntactical advantages to writing Scss instead of CSS though, especially with nesting and mixins.

Emmanuel Any "advantages" are massviely outweighed by the disadvantages -- the biggest of which being that your deployed code bears zero resemblance to your development code! That hobbles your ability to fix when things go wrong.

Take "nesting" where if you look at just a selector in the SCSS version you have no idea what it's relative to unless you scroll up. That's stupid. It's made all the more stupid by the 'compiled' selector being entirely different meaning good luck even finding what the document inspector is telling you in your working source! Any alleged clarity it provides is destroyed by the imprecise selectors. MORE of a problem when a wrapping parent is an ID or class and you land in specificity hell.

... or mixins, which are pointless garbage if you bother just grouping your like selectors. Complete waste of time, effort, and code for ZERO legitimate benefit!

Though to be fair, I say the same thing about CSS "variables".

Again though the big questions remain -- is your deployment environment the same as your testing? What is your DE is it something like nw.js/electron/uwp or are you deploying for browsers? If deploying for browsers are you testing in the same browser? What do other browsers do?

There's a lot that can go bits-up face-down along the way between dev and deploy.