Hever: set proper configuration for main-nav font

hever/sass/_config-child-theme-deep.scss

@@ -324,6 +324,7 @@ $config-header: (
 		// Fonts
 		"font": (
 			"family": map-deep-get($config-global, "font", "family", "secondary"),
+			"family-css-variable": '--font-base',
 			"size": map-deep-get($config-global, "font", "size", "base"),
 			"weight": bold,
 			"line-height": 1,

hever/style-rtl.css

@@ -2541,7 +2541,7 @@ body:not(.fse-enabled) .site-description {
 	color: #303030;
 	display: block;
 	font-family: "PT Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
-	font-family: var(--font-headings, "PT Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif);
+	font-family: var(--font-base, "PT Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif);
 	font-weight: bold;
 	padding: 4px 0;
 }

hever/style.css

@@ -2558,7 +2558,7 @@ body:not(.fse-enabled) .site-description {
 	color: #303030;
 	display: block;
 	font-family: "PT Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
-	font-family: var(--font-headings, "PT Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif);
+	font-family: var(--font-base, "PT Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif);
 	font-weight: bold;
 	padding: 4px 0;
 }