I've just installed Linux Mint 17.3 Xfce edition on a laptop and went on to install Eclipse Mars.2 after I have finished playing with colors everywhere.
I've downloaded the gzipped tarball and extracted it in my home, started it, and got this bad surprise:
I've already tried this but as you can see on the screenshot, it didn't work
I've been searching and tinkering css files for now, in /usr/share/themes but haven't been successful (I'm not even sure which theme I'm using).