themes-wordpress/modern-business/sass/variables-site/_fonts.scss

/*
* IBM Plex Sans (Google Font)
*/

// Font and typographic variables

$font__body: "IBM Plex Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
$font__heading: "IBM Plex Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
$font__code: Menlo, monaco, Consolas, Lucida Console, monospace;
$font__pre: "Courier 10 Pitch", Courier, monospace;

$font__size_base: 22px;
$font__size-ratio: 1.125;

$font__size-xxs:   1em / (1.5 * $font__size-ratio);		// 22 / 1.6875	 = 0.592em	 = 13.037037px
$font__size-xs:    1em / (1.25 * $font__size-ratio);	// 22 / 1.40625	 = 0.7111em	 = 15.6444px
$font__size-sm:    1em / (1 * $font__size-ratio);		// 22 / 1.125	 = 0.8888em	 = 19.5555px
$font__size-md:    1em * (1 * $font__size-ratio);		// 22 * 1.125	 = 1.125em	 = 24.75px
$font__size-lg:    1em * (1.5 * $font__size-ratio);		// 22 * 1.6875	 = 1.6875em	 = 37.125px
$font__size-xl:    1em * (2 * $font__size-ratio);		// 22 * 2.25	 = 2.25em	 = 49.5px
$font__size-xxl:   1em * (2.5 * $font__size-ratio);		// 22 * 2.8125	 = 2.8125em	 = 61.875px
$font__size-xxxl:  1em * (3 * $font__size-ratio);		// 22 * 3.375	 = 3.375em	 = 74.25px

$font__line-height-body: 1.8;
$font__line-height-pre: 1.6;
$font__line-height-heading: 1.2;
$font__line-height-double:  2 * $font__line-height-heading;