Copy room style and colors

Is it possible to copy the style and colors (including lightning) from one room and applying it on just one another room, ie not the entire base?

Not to my knowledge but someone else might know better.

Nope.
You can apply a single particular styling to an entire room, or an entire base ... but you can't copy/paste a room's colors and styling directly onto a <pick room from list> menu (simply because such a UI element does not exist).

It's the end. But the moment has been prepared for ...

Thanks, just thought I've missed something obvious

What you can do is this:

When you're editting styles, there is an option to flip from room to room. (In one of the edit style windows, there are left and right arrows that take you from room to room.)

Start in the room that already has the style you want, and flip to the room that you want to match it to. It should be relatively simple to match the floors, ceiling and walls... because, well, there's not that many different styles.

Lighting colors are a little harder, but not significantly so. Just note the place on the light bars in the first room, and match them in the second room. This may take you a few tries, but it can be done. (One easy way is to use sticky notes or "white out tape" on your monitor to "block off" where the color placements are. And yes, the "white out tape" peels right back off.)

I did this the other day in my tiny base to get the brickwork to all be the same color, so it can be done.