Header color schemes are kept in the directory /ja_purity/styles/header. Editing the CSS file will change the colors.
To add a new color scheme: 1) Create a new directory under /ja_purity/styles/header called by your color's name (i.e. gray). 2) Copy all the contents (including sub-directories) of one of the other directories (i.e. blue) into this directory. 3) Edit the style.css file to have the colors you want. For instance the following changes will make a readable set of colors:
#006699 -> #CCCCCC; #C3DFED -> #444444; #1E7CAB -> #BBBBBB.
4) Edit the images to make them the colors you want. 5) Select the color for your new directory in the template manager.
Remember to religiously refresh. reload, etc. to get the colors to show up.