fix: Add null check to removeStyleElement (#245)

Author: brandondurham

lib/addStyles.js

@@ -166,10 +166,10 @@ function insertStyleElement (options, style) {
 }
 
 function removeStyleElement (style) {
+	if (style.parentNode === null) return false;
 	style.parentNode.removeChild(style);
 
 	var idx = stylesInsertedAtTop.indexOf(style);
-
 	if(idx >= 0) {
 		stylesInsertedAtTop.splice(idx, 1);
 	}