How to make scrollbar visible?


I am on Linux Mint Mate 18.1 64 and I need a good editor badly! I’ve installed Atom with its default dark theme and I find it next to impossible to use its scrollbar. Its handle turns into tiny dark gray point on black screen and I find it extremely difficult to find it or point and click it.

Please guys, help and tell me how to configure this damn scrollbar to be always visible, light gray, 5 mm thick with a normal big handle. No animation, no round corners, no auto hiding etc. please!