Unicorn theme map position off when there are many nav items

[brianherbert]

Originally reported by @heatherleson

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There appears to be a map render issue with the latest crowdmap version. Map does not center right. maybe a theme issue, maybe core patch.
Screenshot - http://cl.ly/image/0l2K3Y092q2X

Using FF

[kamaulynder]

The map issue looks like its sorted but the messed up navigation issue is still there > http://grab.by/jwvK

[rjmackay]

I've got a rough css fix - its still not great when it overflows, but better than before