anchor.diff:  
   # basic colors ---------------------------------------------------------
   #     name        foreground  background  pattern
  -color normal      color8      color15
  +color normal      color0      color15
   color error       color1      color15
  -color tilde       color8      color15
  -color message     color8      color15
  +color tilde       color0      color15
  +color message     color0      color15
   color markers     color1      color15
   color attachment  color20     color15
   color search      color2      color15
  
positive.code: color indicator   color19     color7
  color tree        color7      color15                 # arrow in threads
  
  color index       color8      color15      "~A"       # all messages
  color index       color1      color15      "~F"       # flagged messages
  color index       color8      color15      "~v~(!~N)" # collapsed thread with no unread
  color index       color4      color15      "~U"       # unread messages
  color index       color4      color15      "~v~(~N)"  # collapsed thread with some unread
  color index       color1      color15      "~v~(~F)"  # collapsed thread with some flagged
  
negative.code: color header      color19     color21     "^(Subject)"
  
  # body
  color normal      color0     color15
  color underline   color0     color15
  color bold        color0     color15
  color signature   color20     color15
  
  color quoted      color3      color15
  