More colors from child theme

Hi,
I’d like to know the right way I can add new colors from understrap child theme, and merge it to primary, secondary, dark, light, so the background ant text classes generate when sass are compiled.

For example, create new colors:
$terciary
$corporate

Generate classes
bg-terciary bg-corporate text-terciary text-corporate and so on.

I can see this array in bootstrap _variables.scss, but I can’t figure out how to add colors there from understrap or from undestrap child theme

$theme-colors: map-merge(
(
“primary”: $primary,
“secondary”: $secondary,
“success”: $success,
“info”: $info,
“warning”: $warning,
“danger”: $danger,
“light”: $light,
“dark”: $dark
),
$theme-colors
);

Thanks in advance