An example of how to change the Opera Browser's scrollbar color.
(Install:)
(1:) Open the Opera browser.
(2): Ctrl + Shift + E .
(3): Toggle "Developer Mode" on, it's next to the search extensions bar.
(4): Load unpacked.
(5): Select the folder "unpkd_DevColors".
(6): Set "Allow access to search page results" to true.
(Test:)
Go to a webpage with a scrollbar. If it's working; you'll see a red bar, and a blue bar if you refresh.
- IM-EVIL