.bar.bar-nav doesn't display on iphones 
We're using `ratchet` and `snapjs`, and the header `.bar.bar-nav` doesn't appear properly on iphones. I think that `snapjs` uses some `translate` directives which screw up the ability to display the header because it uses `position: fixed`.

Found this issue on stack overflow which seems to match: http://stackoverflow.com/questions/2637058/positions-fixed-doesnt-work-when-using-webkit-transform

When I add

```
.bar.bar-nav {
  -webkit-transform: translateZ(10px);
}
```

It seems to fix it, and appears correctly on iphones again.
Not sure if this is the best solution or not, but it fixes our problem.
