Colour issue in drak mode. (Kali 20.1)

[Ankit Verma]

Dark blue colour really hurts eyes in dark mode. Text colour is not changing according to dark mode.

[Robert Spiegel]

see https://github.com/robert7/nixnote2/wiki/NixNote-Themes

[xxpol]

Possible improvement: In dark mode (Arc dark), highlighted text in 'search' is white on bright yellow background; text is almost invisible.