SASS (Syntactically awesome stylesheets)/LESS (not an abbreviation) are CSS pre-processors. If you haven't heard of them then you should jump in now and start using them.Simply put, these two languages compile down into vanilla CSS, but add many timesaving features and utilities to speed up frontend design & maintenance.As of SCSS (it's previous incarnation, used a different indentation-based syntax), both these languages are supersets of CSS. This means ...