How Do I Change Text Selection Highlight Colour?

[opticyclic]

I am using the latest Vivaldi snapshots on Ubuntu 17.04 with KDE.
When I select text with Firefox the selected text is highlighted in a blue background.
When I select text with Vivaldi the selected text is highlighted in white background (!)

This is essentially no highlighting at all. How do I change the background colour of highlighted text?
I can't see an option to tweak it in the themes section.

[Steffie]

@opticyclic Hmmm. For me:

...but i also have previously wondered how V does it, coz it's not coming from my KDE5 System Settings' colours:

[Marko Indaco]

Also, if I understand well, the highlight search color should be the same that you choose in Settings --> Themes

[opticyclic]

@Marko-Indaco said in How Do I Change Text Selection Highlight Colour?:

Also, if I understand well,

I don't think you do

I am talking about the background colour when you select text on a webpage.
If you look at your screenshot you are changing the font colour of the chrome elements.

[opticyclic]

@Steffie
It doesn't match my System Settings either.
However, I managed a workaround with this extension
https://chrome.google.com/webstore/detail/highlight-color/dllbflhpdeinobodaaibnojmgejkkjii