Here is a thread on how you can change it with themes, but from the discussion there, it seems like Windows 11 may have broken it. So that aside, yes, you can change the colour in Windows settings. I do, because the default shock white is so obnoxious.
To the point though: this isn’t technically a part of Scrivener, but of Windows. Where you see otherwise, the developers have specifically removed the standard title bar and then reinvented their own.