I've spent many weeks playing with the stylesheet, and have now created one to my satisfaction. Its basically trying to mimic
the old Sandbox 386 version. Blues , then I added some pastel green - Not all of you may like it , but I feel its better than Black.
The style sheet contains notes about colors - thats why its bigger than the original black version. There may be errors - and bits not done.
But hey, I'm not familiar with the QT stylesheet system. Please feel free to change it as you will.

For those who are new to this put the unzipped stylesheet.qss at this address. back up the old file first.
your cryengine directory / cryengine_5.6 / Editor / Styles / stylesheet.qss

Then run the Sandbox editor and all the black will turn to color.

Hi pharris,
thank you for sharing!