Java cross-platform look and feel for JRE 1.6 update 17 and later. This is based on Nimbus, but is lighter in color and based on forms seen in sea glass, that is, glass washed up on the shore by the sea.
See the project documentation for more information.
The test project is in http://seaglass.googlecode.com/svn/seaglass-demo and available for checkout.
We started with some preliminary artwork and then ended up with some changes as we saw how everything worked together and got feedback from users.
Here is the current look, taken from seaglass-demo.jar:
Spinner and Combo boxes
Progress bars and sliders
Split pane divider
Tables and tabs
Note that on Mac OS X we use the Mac look and feel for the windows chrome and toolbar since Mac users are very particular about this.