Change system-wide selection background color?

Hello,

Windows 10 Pro Version 1511 build 10586.420. with UI customizations using Winearo Tweaker, Classic Shell, and registry modifications. After Windows update KB3163018 (June 22, 2016), I disabled the Windows Update service. Now the only thing I still can't stand about my UI is the standard light blue background color when I select text and things.

I installed Windowblinds 10 trial, but I guess "Change System Color" is in Skin Studio, which is not part of the trial version. My question is: if I buy the full version including Skin Studio, will I be able to change that selection background color in Windows and all the programs (not apps) that use it, including Firefox etc.?

Note: The only app I use is PC Settings, and of course, that has another (light grey) selection background color. I suspect even Skin Studio won't be able to change it. I could live with that...