Automattic developers have just announced that they have added support for SASS and LESS in their two platforms.
Users of WordPress.com and Jetpack for WordPress.org can now use these CSS preprocessors in the CSS editors on their blogs.
WordPress would then handle the compilation to regular CSS at runtime.
The two most popular CSS preprocessors are SASS and LESS, and they’re both available today in the CSS Editor on WordPress.com and the Jetpack plugin for self-hosted blogs. To use either language for your Custom CSS, just change the Preprocessor option before you save, and your SASS or LESS will automatically be compiled into CSS when it’s served to your site’s visitors.