css + class with utf-8 chars Follow

PhpStorm 4 shows error in css classe names with utf-8 characters.

According to w3c spec http://www.w3.org/TR/CSS21/syndata.html#characters

In CSS, identifiers  (including  element names, classes, and IDs in  selectors) can contain only the  characters [a-z0-9] and ISO 10646  characters U+00A1 and higher, plus the  hyphen (-) and the underscore (_);  they cannot start with a digit, or a  hyphen followed by a digit.

so this should be valid.
Do i miss something, or it's bug?