Thus we would need variables that are common in most templates and
should be documented as required for templates and available for
plugin developers:
__body_text_color__
__body_bg_color__
__link_color__
__link_color_visited__
__link_color_hover__
__link_color_active__
__header_bg_color__
__header_text_color__
__footer_text_color__
...