proven! bright screens make us sick; please implement black-background viewing option as in excel and calc

[marc dunord <marcdunord gmail com>]

i implore you guys/gals again!

please implement a black-background viewing option as those offered by
excel and calc...

see link below:  bright screens make us sick !  :(

http://www.guardian.co.uk/science/2013/may/22/peering-bright-screens-dark-harm-health

it would be enough to just reverse colors (like a photo negative) and
keep the printing as if one worked with a bright-background screen.

as offered by pdf viewers in linux and windows...

best

   marc