Sass is incredibly elegant and generates CSS far more efficiently than the Joomla default pre-processor, LESS.
That said, the two leading pre-processors are remarkably similar in many respects, so if you are familiar with LESS will have no trouble in quickly understanding what Sass is doing. You will also quickly understand from viewing the output of Sass why it has quickly become the only choice for professional front-end developers.
Don't like pre-processors?
No problem, you can still modify our templates by simply editing /css/style.css in the old-fashioned way. You are missing out on a lot of the magic though…