Color module doesn't do anything with my css

Hello,

I'm pretty much a newbie and I have been struggling with this problem for a long time without finding a solution.

Problem:
I use the color module and when modifying colors with the color picker new images gets saved in default/files/color/my_theme-xxxxxxxx
But NOTHING happens with the css. What have I done wrong?
My current css-files is saved in all/sites/themes/my_theme/css

Any help is greatly appreciated!!