Use font size array
Created by: academici
$font-size-base: 1rem !default; // Assumes the browser default, typically `16px`
$font-sizes: () !default;
$font-sizes: map-merge((
"base": $font-size-base,
"sm": ($font-size-base * 1.25),
"lg": ($font-size-base * .875),
), $font-sizes);
div {
font-size: font-size("sm")
}