monokai theme for texstudio. save in ~/.config/texstudio/texstudio.ini while Texstudio is closed (texstudio must be closed first as it writes to the ini file when it closes).
Taken from Hyndsight, a blog by Rob J Hyndman: http://robjhyndman.com/hyndsight/dark-themes-for-writing/ and stored here for my own personal use.
more themes are here: https://tex.stackexchange.com/questions/108315/how-can-i-set-a-dark-theme-in-texstudio