debugf が白地に赤でちょっと見辛かったので。
$Log::Minimal::DEFAULT_COLOR->{debug} = { text => 'blue', background => 'black', };
色名は Term::ANSIColor で使えるやつ。
The recognized normal foreground color attributes (colors 0 to 7) are: black red green yellow blue magenta cyan white The corresponding bright foreground color attributes (colors 8 to 15) are: bright_black bright_red bright_green bright_yellow bright_blue bright_magenta bright_cyan bright_white