Now on the ribbon bar, click on the little arrow at the bottom right of the 'Styles' group, which should give you a drop-down list of Styles. At the bottom of this list is a 'Manage Styles' button - hit that, and the list of styles comes up with a 'Modify' button at the bottom. Just choose the style whose colour you want to change, hit 'Modify', and change the colour etc.
Save the file when you're done, close it, and move it back into the STARTUP folder and re-start word. Now you should get the new colours.