fixed "font" property parsing

lib/single-file/modules/css-fonts-minifier.js

@@ -179,12 +179,15 @@ this.fontsMinifier = this.fontsMinifier || (() => {
 		const font = declarations.children.filter(node => node.property == "font").tail;
 		if (font) {
 			let familyName = "";
-			const findPreviousComma = node => {
-				for (; node && !(node.data.type == "Operator" && node.data.value == ","); node = node.prev);
-				return node;
-			};
 			if (font.data.value.children) {
-				for (let node = font.data.value.children.tail; node && (node.data.type != "WhiteSpace" || findPreviousComma(node)); node = node.prev) {
+				let startNode = font.data.value.children.head;
+				while (startNode && startNode.data.type != "WhiteSpace") {
+					startNode = startNode.next;
+				}
+				if (!startNode) {
+					startNode = font.data.value.children.head;
+				}
+				for (let node = font.data.value.children.tail; node && node != startNode; node = node.prev) {
 					if (node.data.type == "Operator" && node.data.value == "," && familyName) {
 						fontFamilyNames.push(getFontFamily(familyName));
 						familyName = "";