XamarinDevDays/Demos/app-myweather/MyWeather.Droid/Resources/values-v21/style.xml

<?xml version="1.0" encoding="utf-8" ?>
<resources>
    <style name="MyTheme" parent="MyTheme.Base">
        <item name="android:windowDrawsSystemBarBackgrounds">true</item>
        <item name="android:statusBarColor">@android:color/transparent</item>
    </style>
</resources>