Bug 476051

In Konsole, I often want to split the tab with several views. I also use Breeze Dark theme.

The problem is that default profile is always on dark background, while the splitter color is the same as titlebar color. This causes it to be hardly visible on dark theme (see screenshots).

STEPS TO REPRODUCE
1. Open the Konsole
2. Select Settings | Window Color Scheme | Breeze Dark
3. Press Ctrl + Shift + ) or View | Split View | Split View Top/Bottom.
3. Try to see where is the splitter

OBSERVED RESULT
You cannot see it clearly

EXPECTED RESULT
You should be able to see it.

Firstly, I thought that the QSplitter color should depend on the terminal background color. But then I thought that in the same tab the profile (i.e. background color) may be different for each split view.

So my suggestion is to use always working approach - a splitter with the color of window theme, but surrounded with tiny line of inverted color.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.111.0
Qt Version: 5.15.11
Kernel Version: 6.5.8-arch1-1 (64-bit)
Graphics Platform: Wayland
Konsole: 23.08.2

ADDITIONAL INFORMATION
I saw some email clients do this approach for emails that do not care of users preference. They can remove light background from image, but they keep a small border to be on a safe side (if image is dark, its border should be visible).

By the way, Dolphin also has a split view, and it looks good with dark theme.