For a long time, I thought the color of the divider in the Synopsis pane could not be changed. I even put it on the WishList in the L&L Community Forum. It was recorded as a bug, though.
Then I stumbled on the solution trying to change the textcolor of the Synopsis pane in the Inspector, which came as a surprise:
>> Looking into the Synopsis text color, I’ve come up with this:
>> SCRIndexCardWidget QWidget {color: lime;}
>> But it comes with a surprise. I hope you like it anyway.
For you, the surprise is reversed: you’ll have to deal with divider similar colored as the text.
So, choose wisely. 