In PowerShell >6.0 I can change the command line FOREGROUND colors with:
Set-PSReadLineOption -Colors @{ Keyword="#0FAFE0"; Variable="#987ABC" }+
but how do I change the BACKGROUND colors with RGB??? (#RRGGBB)
i can see some examples with ASCII console sequences
but none with the RGB format
I don't think you can? SelectionColor uses the ansi escape code for black on white: "`e[30;47m" (ps 7 for the `e). https://en.wikipedia.org/wiki/ANSI_escape_code#Colors
How about this from that wikipeda page:
Red foreground (255 0 0) blue (0 0 255) background.
In ps5 you have to say $([char]0x1b) instead of `e.