You could manually set it via terminal (no devel mode needed)

open terminal (or use ssh) and then paste the following
Btw.

To view the currently set colors type:
for example yours should then look like this

highlight = #ffff00
primary = #ffffff
secondaryHighlight = #aeb404
secondary = #ffffff

while

highlight = the main notification (pulley) color and the tint of the home screen
primary = the color of the clock, entries in pulley menu and settings, as well as active radio buttons or sliders (like volume in settings for example)
secondary = unhighlighted, greyed out text
secondaryHighlight = greyed out entries in sub sub pulley menus

For dark or black and white walls I use:

This is just a quick and dirty hack from together.jolla but if you don't change ambience then it will stay even after reboot.

You can get your color codes here if you need: http://www.w3schools.com/tags/ref_colorpicker.asp

Regards,

J4ZZ