Software used to create Blender's UI

Hi all,
I’d like to know which software was used to create Blender’s UI?
By this I mean the tabs, panels, node editor and the like.
Thanks for the answers.

C (programming language) and inkscape for the icons.

As far as my understanding goes blender implemented their own UI framework hence why its cross platform.
3dsMax and Maya use QT these days but back in the days had different frameworks for each platform.

Holy f****ing $**t. As if building a rendering engine, physics engine, the viewport, artistic toolkits weren’t hard enough.
I think I’ll take a look at Qt, they have a decent open source licence. My other options would be WPF, Java Swing which are decent tools, but it would be a royal pain in the a$$ to make that gui in those. Thanks for the answer :slight_smile: