Varia: migrate sass/blocks/button

varia/sass/blocks/button/_editor.scss

@@ -4,7 +4,8 @@
 	.wp-block-button__link {
 		color: #{map-deep-get($config-button, "color", "text")};
 		font-weight: #{map-deep-get($config-button, "font", "weight")};
-		font-family: #{map-deep-get($config-button, "font", "family")};
+		font-family: #{map-deep-get($config-button, "font", "family")}; // For browsers that don't support CSS variables.
+		font-family: var( --font-headings, #{map-deep-get($config-button, "font", "family")} );
 		font-size: (strip-unit(map-deep-get($config-button, "font", "size")) + 0em);
 		line-height: #{map-deep-get($config-button, "font", "line-height")};
 		background-color: #{map-deep-get($config-button, "color", "background")};

varia/sass/blocks/button/_style.scss

@@ -10,6 +10,7 @@
 	cursor: pointer;
 	font-weight: #{map-deep-get($config-button, "font", "weight")};
 	font-family: #{map-deep-get($config-button, "font", "family")};
+	font-family: var( --font-headings, #{map-deep-get($config-button, "font", "family")} );
 	font-size: #{map-deep-get($config-button, "font", "size")};
 	background-color: #{map-deep-get($config-button, "color", "background")};
 	border-radius: #{map-deep-get($config-button, "border-radius")};

varia/style-editor.css

@@ -257,6 +257,7 @@ object {
 	color: white;
 	font-weight: bold;
 	font-family: sans-serif;
+	font-family: var(--font-headings, sans-serif);
 	font-size: 1.2em;
 	line-height: 1;
 	background-color: blue;
@@ -1389,6 +1390,7 @@ body:not(.fse-enabled) .footer-menu a {
 	cursor: pointer;
 	font-weight: bold;
 	font-family: sans-serif;
+	font-family: var(--font-headings, sans-serif);
 	font-size: 1.2rem;
 	background-color: blue;
 	border-radius: 9px;

varia/style-rtl.css

@@ -541,6 +541,7 @@ html {
 html {
 	font-size: 15px;
 	font-family: serif;
+	font-family: var(--font-base, serif);
 	line-height: 1.78;
 }
 

varia/style.css

@@ -1041,6 +1041,7 @@ input[type="submit"],
 	cursor: pointer;
 	font-weight: bold;
 	font-family: sans-serif;
+	font-family: var(--font-headings, sans-serif);
 	font-size: 1.2rem;
 	background-color: blue;
 	border-radius: 9px;