Hi Wolfgang
Two ways come to may mind:
- You can load templates as you mentioned above by the skin (not PHP files or similar). Also see: https://github.com/ILIAS-eLearning/ILIAS/tree/trunk/templates#system-styles for details. In those templates you probably could pull some JS-Magic by replacing the global il.Explorer2 from the il scope of the ILIAS client side. So you could place there your own Explorer2 version. This requires some JS skills however and is not the way I would go.
- You can override the inline-css by overriding them with importent (!) statements in your skins CSS. This is nasty as well but should be strait forward.
As you see, both options are ugly. Maybe somebody points out a better one, but I think everybody agrees that the current implementation of Explorer and the concrete instances need some refactoring including accoring less variables for easy styling. They way forward would be to add the explorer the the Centralized UI Framework (aka Kitchen Sink), if you interested in supporting this, please contact me.