Font family names must either be given quoted as strings, or unquoted as a sequence of one or more identifiers. This means most punctuation characters and digits at the start of each token must be escaped in unquoted font family names.
(...)
For example, the following declarations are invalid:
(...)
font-family: Hawaii 5-0, sans-serif;
But such declaration is not reported as invalid by the CSS validator. Please press the CSS button below.