Varia: add missing comment

varia/sass/blocks/posts-list/_style.scss

@@ -11,7 +11,7 @@
 .a8c-posts-list-item__featured span {
 	color: #{map-deep-get($config-global, "color", "background", "default")};
 	background-color: #{map-deep-get($config-global, "color", "primary", "default")};
-	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 variables.
 	font-family: var( --font-headings, #{map-deep-get($config-global, "font", "family", "primary")} );
 	font-weight: bold;
 	font-size: #{map-deep-get($config-global, "font", "size", "sm")};

varia/sass/blocks/utilities/_style.scss

@@ -212,7 +212,7 @@
 
 // Drop caps
 .has-drop-cap:not(:focus)::first-letter {
-	font-family: #{map-deep-get($config-heading, "font", "family")};
+	font-family: #{map-deep-get($config-heading, "font", "family")}; // For browsers without support for CSS variables.
 	font-family: var( --font-headings, #{map-deep-get($config-heading, "font", "family")} );
 	font-size: calc(2 * #{map-deep-get($config-heading, "font", "size", "h1")} );
 	font-weight: #{map-deep-get($config-heading, "font", "weight")};