NetBeans comes with "Compile On Save" and editing support for http://sass-lang.com and http://lessframework.com out-of-the-box. No plugins required.
See you at Java EE User Interfaces, HTML 5 or Virtual Dedicated Workshops / consulting!
Three days in April 2017: from Java EE 7 Architectures over Microservices to Performance, Troubleshooting and Monitoring
On demand workshops: Java EE 7: Bootstrap, Effective, Testing and Microservices available for streaming.
A book about rethinking Java EE Patterns