Apparently Niko Kovac doesn't think his team is good enough at their national anthem so they spent time in training practicing it. Like actually lining up, putting their hands over their hearts and singing it.
The Croatian national anthem isn't overly complicated either. It's only four verses long and a pretty simple melody, but as wonderful as Croatia may be at soccer, they aren't so great at song memorization or singing*.
So long after Croatia are eliminated from the World Cup they will be able to look at their trophy case and see their reward for a summer's worth of sweat and tears there -- Best Anthem Hustle, Brazil 2014.
* Luka Modric does not need anthem practice because he does everything perfectly.