black os_ison on white background in rainbow style. otherwise it sucks on both MS terminals as they cannot differentiate between black and no background

config/p10k-rainbow.zsh

@@ -188,8 +188,8 @@
 
   #################################[ os_icon: os identifier ]##################################
   # OS identifier color.
-  typeset -g POWERLEVEL9K_OS_ICON_FOREGROUND=255
+  typeset -g POWERLEVEL9K_OS_ICON_FOREGROUND=232
-  # typeset -g POWERLEVEL9K_OS_ICON_BACKGROUND=0
+  typeset -g POWERLEVEL9K_OS_ICON_BACKGROUND=7
   # Make the icon bold.
   typeset -g POWERLEVEL9K_OS_ICON_CONTENT_EXPANSION='%B${P9K_CONTENT}'
 

internal/wizard.zsh

@@ -93,7 +93,7 @@ typeset -ra pure_right=(
 )
 
 typeset -ra rainbow_left=(
-  '%$frame_color[$color]F╭─' '%F{${${extra_icons[1]:+0}:-4}}$left_tail${extra_icons[1]:+%K{0\} $extra_icons[1] %K{4\}%0F$left_sep}%K{4}%254F $extra_icons[2]%B%255F~%b%K{4}%254F/%B%255Fsrc%b%K{4} %K{2}%4F$left_sep %0F$prefixes[1]$extra_icons[3]master %k%2F$left_head%f'
+  '%$frame_color[$color]F╭─' '%F{${${extra_icons[1]:+7}:-4}}$left_tail${extra_icons[1]:+%K{7\} $extra_icons[1] %K{4\}%7F$left_sep}%K{4}%254F $extra_icons[2]%B%255F~%b%K{4}%254F/%B%255Fsrc%b%K{4} %K{2}%4F$left_sep %0F$prefixes[1]$extra_icons[3]master %k%2F$left_head%f'
   '%$frame_color[$color]F╰─' '%f ${buffer:-█}'
 )
 
@@ -773,8 +773,10 @@ function ask_extra_icons() {
     time_icon=${time_icon// }
   fi
   branch_icon=${branch_icon// }
-  if [[ $style == (classic|rainbow) ]]; then
+  if [[ $style == classic ]]; then
     os_icon="%255F$os_icon%f"
+  elif [[ $style == rainbow ]]; then
+    os_icon="%F{232}$os_icon%f"
   else
     os_icon="%f$os_icon"
   fi
@@ -1747,6 +1749,7 @@ while true; do
     ask_time            || continue
     ask_separators      || continue
     ask_heads           || continue
+    ask_extra_icons     || continue
     ask_tails           || continue
     ask_num_lines       || continue
     ask_gap_char        || continue