Change text color of selected preference items

[mintefrsh]

I'm using Mint 18.1 & a custom theme, Cinnamonx Heather.
It seems to change the font color in several apps on screens like Preferences -in apps like Gimp, Shutter, PassWord Safe (Linux).

I can't find what identifier this would be called in gtkrc (I assume) so I can darken the text - when hovered AND when preferences are selected. In the image, what are pages / boxes & the options on them named - for themeing purposes?

The preference boxed in red was being hovered when the shot was taken. If you check items, then text stays white.

On main menus, it also changes text color of hovered items to white, but in menus it also changes the background of hovered items, for better contrast.