Flux (http://tinyurl.com/yazuwbr), the web design application for Mac OS X, has been revved to version 5 (or “V,” as its developers dub it). The software can work with everything from a modern site using HTML5 and CSS3 to legacy sites built on older technologies.

Flux V comes with a totally redesigned user interface. It’s more tuned for use as a full-screen application, and more compact for smaller laptop screens. It’s also now fully 64-bit, fully ARC-compliant and multi-threaded. This means Flux is faster, more stable, and will make better use of the multiple cores in your modern Mac.

The software has re-worked the core feature set. FreeCode is the only way Flux works now; this means non-standard HTML is fully editable. It also means that Flux can work with everything from a modern site using HTML5 and CSS3 to legacy sites built on older technologies.

Flux V has a brand new Master Elements system. It works in both CSS and HTML files, and lets you use elements of one page in another page and when the original page is changed, Flux can apply those changes to the rest of the pages that use those elements.

The new version also sports crowd sourced code. Users can submit their own code to other Flux V users to help each other with their sites.

A 30-day demo is available for download. Registration is US$109 for new users; users of previous versions can upgrade to version 5 for 50% off. Flux V requires Mac OS X Mavericks or the upcoming Yosemite.