Is it possible to change the colors of the Opera interface elements?

Question

Opera

Not just a theme (background image in the express panel) but interface elements; frame, toolbar, bookmarks, background.
For Chrome , there are plugins and services, such as this one , but for Opera, something is not.
All in all, this is confusing! How so?! - in the main program of the computer - a web browser and not to implement the choice of the color scheme of the skin? After all, even in MTS Connect Manager it is! in archivers, not to mention mp3 players...
Is it really so complicated and resource-intensive - a 500-byte text with a dozen groups of HTML color codes....