In dev diary I'm still reading about LESS. Guys it's 2018, let's bring back SCSS thread from 2015.
Latest update: 5 days ago. https://github.com/leafo/scssphp/
So it is more than well maintained.
Back from 2012 https://css-tricks.com/sass-vs-less/
In 2018 https://www.slant.co/versus/763/764/~less_vs_sass
SCSS is like pure CSS but steroids are always on the bench to use if you want to get full power. So learning curve start at zero.
