add quotes arround url() method parameter .
@ -201,7 +201,8 @@ const Property = Backbone.Model.extend(
}
if (fn && hasValue) {
value = `${fn}(${value})`;
const fnParameter = fn === 'url' ? `'${value}'` : value;
value = `${fn}(${fnParameter})`;
if (hasValue && this.get('important')) {