I am developing some Chrome app and started using Ubuntu colours for it. The ones I found in the Ubuntu Colour Palette. I assume it's there and public so that app developers could create a consistent experience for Ubuntu users. What about apps that do not aim at Ubuntu users? Like in my case - a browser extension. Is it legal to use these colours wherever I want or will it be considered a violation of a trademark/brand use?
I searched for terms of use of the colours but couldn't find any. I just assume it is copyrighted as a part of a brand/trademark.
P.S. I am an Ubuntu user and, as I consider my self as a primary user for the extension, I wanted an Ubuntu-like experience for myself. However, I am going to publish it so that more people could benefit from it and that's where the problem comes from.