At online demos, exists a new theme called mltheme
How I can add this in system already installed ?
That's the theme I created some years ago. You can download it
here. Just copy the folders in the 'themes' folder in the ZIP into the 'themes' folder in your corebos installation. I haven't used it in a couple of years so a lot may have changed in the meantime, I don't know if it still works correctly, but if you have questions let me know.