Accent color for windows and borders for using both the dark theme and the light theme altogether.

**Describe the enhancement or feature you'd like**
I would Like both the accent color for both of these modes as it would give me a sense of personality.
**Describe alternatives you've considered**

**Additional context**

No files, tests, or entry points are identified in the issue. First clarify how accent colors and window borders should behave when dark and light themes are used together, then locate the theme and border customization code; done means both modes visibly apply the requested colors without disrupting theme switching.

Written by the indexing model from the issue text.