fixed font size parsing

lib/single-file/vendor/css-font-property-parser.js

@@ -304,7 +304,7 @@ this.fontPropertyParser = (() => {
 	}
 
 	function isSize(value) {
-		return /^[d.]/.test(value)
+		return !isNaN(parseFloat(value))
 			|| value.indexOf("/") !== -1
 			|| cssFontSizeKeywords.indexOf(value) !== -1;
 	}