Nowadays every major software companies are introducing the dark theme in their software but Microsoft is planning to introduce a light theme in an upcoming Windows 10 update.
This update allows all the UI to appear white. Microsoft is also modifying its default wallpaper for the window to match the light theme.
If you are part of windows insider program you can test this feature before its officially available.
Here’s the wallpaper from this theme in 1080p resolution(right click or hold if you’re on mobile and save the image to download it).