Go into your Edit - Preferences - Interface menu. Click your preferred colored Color Theme box near the top.
There's a key sequence that selects a color theme but I forget what it is. That's what you stumbled upon.
many thanks its work
It's Shift+F1 darker, and Shift+F2 lighter.
While I'm on the subject, I get the impression that the importance of interface color is underestimated. It actually has a huge impact on the perceived brightness of the image on-screen. The new(ish) dark interface is very easy on the eyes, and great for web and video work - IOW images destined for screen. But for print you can easily be tricked by the dark environment and end up with the classic "my prints are too dark". I would say that the old and boring light interface gives you a much more reliable preview of what the finished print will look like.
The same consideration applies to Lightroom BTW. Here you can't even choose, except you do have the option for a light main window backdrop, which helps (although the whole UI gets messy and inconsistent).
Yes, that's true. Beyond visually checking prospective prints on a bright surround, it's a good reason to get in the habit of glancing at the Histogram to get an objective measure of your overall brightness levels. I also set my Info panel to read out in H, S, B and when prepping images for print I hover over the brightest parts of people's skin and look for an ideal B value of between 90% and 95%.
Absolutely. The histogram is another thing that's very underrated (as in "histogram schmistogram. I know what I like" which was a very trendy attitude for a while... )