Lion CSS UI Kit
Mock up native Mac apps in your browser
Any feedback would be greatly appreciated. Tweet to @sakamies
The kit is based on Xcode components on OS X Lion. Since the kit is for prototyping OS X apps, it's mainly made for Webkit, but should work mostly fine in any browser that supports gradients and flexboxes.
Copy & paste is your friend. The html is just form elements with classes, and simple containers for any multi-part controls.
Most of the styles are not tied to any context, so you can just apply a class to style an element in any way you wish. The classes are named after the actual component names in Xcode.