Leven: update _extra-child-theme

leven/sass/_extra-child-theme.scss

@@ -7,7 +7,8 @@ html {
 }
 
 .has-small-font-size {
-	font-family: #{map-deep-get($config-global, "font", "family", "primary")};
+	font-family: #{map-deep-get($config-global, "font", "family", "primary")}; // For browsers without support for CSS custom properties.
+	font-family: var( --font-headings, #{map-deep-get($config-global, "font", "family", "primary")} );
 }
 
 a {

leven/style-rtl.css

@@ -3589,6 +3589,7 @@ html {
 
 .has-small-font-size {
 	font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
+	font-family: var(--font-headings, -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif);
 }
 
 a {

leven/style.css

@@ -3618,6 +3618,7 @@ html {
 
 .has-small-font-size {
 	font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
+	font-family: var(--font-headings, -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif);
 }
 
 a {