SCSS is the primary language syntax. We do try to keep support for the original syntax. Sometimes things slip through when we forgot to test on it, but that's usually just new features. No reason to remove it, in our book. It's the same backing code.

I only have one problem with Less, and it's the way they use classes-as-mixins. It just makes me uncomfortable somehow. But, that's personal preference. Honestly, they are pretty similar, but Sass is a little more standard, plus I invented it, so obviously I have to say that. :)

I don't know... maybe! But, not everything is appropriate to do in the browser. I'd be surprised if we ran out of language-and-syntax improvements that wouldn't be worth the compile time while devving.

The official "Create-React" app puts a twin CSS file next to the JS file. That's what I do. Store.js and Store.scss sit next to each other. And in Store.scss I wrap everything in .Store which is the class of the React Component.

I have one at Rent The Runway... but it's not open source. :)

With postCSS. No, really, that's what I do in my build-stack. Eventually we want that in Node-Sass as an extension, but for now... I just use autoprefixer

Oh, simple. SCSS is CSS compatible. So, if you are at a company, you can add Sass to your build-chain and coworkers who don't want to use it... don't have to! Also, all of your old code works (as long as it was valid!) Adoption was slower when you had to 'learn a new syntax'. SCSS made Sass just... CSS++ I use SCSS syntax now (it's the default), but I do really miss the +myMixin syntax.

Hmmm... I'm not really sure what you mean. React Native is already out. I've been playing with it. I'm not sure how it's related to Sass and/or it's death.

Languages: Java 8, ES6, Ruby, SQL. IDEs: Jetbrains based IDE's... specifically Webstorm and IntelliJ Frameworks: Create-React, Dropwizard, Rails.

Okay, well, I immediately know one. @extends in the browser. Right now, we have to do all sorts of gross-dark-magic things to make @extends work in Sass. It's complex and it mostly-works... but it's complex because we don't know the DOM. If we knew the HTML, we could be super efficient about it. Something with the functionality of @extends would be trivial in the browser, and then we wouldn't have to do it. We only built it because there were so many good use-cases that it overrode our concerns about complexity and maintainability. Another thing I really want is a good CSS-JS bridge. Oh, and I'd love it if nesting was supported. We could still compress our output, but we wouldn't have to repeat selectors over and over in our output!