Using #SCSS you can specify a a set of values in a map for easier access. Declare your map as a variable and reference it with the map-get SCSS function.
$colors: ( "green": #008000, "red": #FF4136, "blue": #0074D9, );
Reference that variable with the map-get function.
.bg-lg { background-color: map-get($colors, "green"); }
Read more about it here