When I became aware of Sublime, I noticed the benefits of dark themes to your workspace. But since Sublime doesn't have support for Grails at the moment, I search for ways to theme STS or SpringSource Tool Suite and I reached to this article. I tried the plugin and it worked well. Unfortunately, only the Editor area was change by the plugin.
The question is how I change the Color and Fonts of the whole STS or Eclipse?
If you use the current STS milestone (STS 3.0.0), then it is possible, because the underlying Eclipse 4 is now completely themeable. There are already some themes available, however you should consider them beta.
Here is a place to pick a color theme for your editing window: http://eclipsecolorthemes.org/