WindowContentOverlay "No resource found matching the specified name"

I am trying to create an app theme with a fully transparent appcompat action bar. I am trying to remove the shadow below the action bar using windowContentOverlay, but for some reason I am unable to build this attribute. Elevation attribute only works for lollipop + devices and my minimum API level is 16.

What is the problem?

Error: (12, 29) No resource was found that matches the specified name: attr 'windowContentOverlay'.

<resources>

<!-- Base application theme. -->
<style name="AppTheme" parent="Theme.AppCompat.Light">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>

    <item name="android:actionBarStyle">@style/TransparentActionBar</item>
    <item name="android:windowActionBarOverlay">true</item>
    <item name="android:windowContentOverlay">@null</item>

    <!-- Support library compatibility -->
    <item name="actionBarStyle">@style/TransparentActionBar</item>
    <item name="windowActionBarOverlay">true</item>
    <item name="windowContentOverlay">@null</item>

</style>

<!-- Transparent Action Bar Style -->
<style name="TransparentActionBar"
    parent="Widget.AppCompat.Light.ActionBar.Solid.Inverse">
    <item name="android:background">@android:color/transparent</item>

    <!-- Support library compatibility -->
    <item name="background">@android:color/transparent</item>
</style>