On my monitor the “darktable-elegant-grey” style shows reddish artefacts in small fonts e.g. within the filmic box (see the “middle grey luminance” text below):
As the standard darktable font works fine I copied “darktable-elegant-grey.css” and “darktable.css” to my personal themes- folder. I then renamed “darktable-elegant-grey.css” to “darktable-grey.css”. In “darktable-grey.css” I changed line 21:
OLD: @import url(“darktable-elegant-dark.css”);
NEW: @import url(“darktable.css”);
“darktable-grey” now uses the standard font with grey settings:
Not as elegant 
but ok for me.
Greets,
Jürgen