##### Is your feature request related to a problem? Please describe <!-- A clear and concise description of what the problem is. Ex. I'm always frustrated when [...] -->
The proposal is simple, improve Dark Mode. For example, the fact that on Windows Geany's Dark Mode does not change the color of the TitleBar is something that frustrates me
##### Describe the solution you'd like <!-- A clear and concise description of what you want to happen -->
For me, implementing [this would be enough](https://learn.microsoft.com/en-us/windows/apps/desktop/modernize/ui/apply-wi...).
Since you are using GTK and not WinAPI to program windows (a pretty obvious choice since this project is not focused on Windows), the [`DwmSetWindowAttribute`](https://learn.microsoft.com/en-us/windows/win32/api/dwmapi/nf-dwmapi-dwmsetw...) function will only work with the window handle. In other words, if you get the window handle using specific GTK functions, you can change the color of the Title Bar. You can also see what the system Color Mode is using the `ShouldAppsUseDarkMode` and `ShouldSystemUseDarkMode` functions.
[Geting Window Handler using GTK](https://stackoverflow.com/questions/9259731/getting-gtk-gdk-window-handle-on...) for exemple...
##### Describe alternatives you've considered <!-- A clear and concise description of any alternative solutions or features you've considered -->
I've already used the method of changing the color of the system's Title Bars, but it's not very cool or interesting as a solution... (but yes, it works)
##### Additional context <!-- Add any other context or screenshots about the feature request here -->
I already made a [similar issue](https://github.com/geany/geany/issues/4036), and it has already been resolved. But it is not the same issue. The big difference is that I would like the problem to be solved with code, within the project, and not on each user's computer (let's face it, having to change a part of the system for each installation just because of 1 application is not very cool...).