# - WHITE: one of the ANSI colour names, in upper case
# - @RRGGBB: a RGB code we will try to match using one of the 256 Terminal colours
# - #RRGGBB: an exact RGB colour (please make sure your terminal supports this)
+# - 255: one of the 256 indexed colours of the terminal (the 16 first colours are theme-based)
#
# ...and thus either for xxx_FG (foreground colour) or xxx_BG (background colour)