I can't believe nobody has properly explained this.... anyway, "anthem", when used stylistically, means theme. For instance, if a venue, such as a dance club, has a contiguous design feel, it can be said that it sticks to an anthem.
Of course it can also mean a song that is used to convey underlying values, principles, spirit, commraderie, etc., eg. a national anthem.
"I appreciate the anthem of this Japanese resteraunt."