issue with rendering header & nav tag ios/andriod

when below html is rendered

```
<header>
<nav>
</nav>
</header>
```

it renders differently on ios/andriod

On Iphone 6

```
<header>
</header>
<nav>
</nav>
```

On Andriod
```
<header>
<nav>
</nav>
</header>
```

