As official docs state:
"If you want to inherit from styles that you've defined yourself, you do not have to use the parent attribute. Instead, just prefix the name of the style you want to inherit to the name of your new style, separated by a period. For example, to create a new style that inherits the CodeFont style defined above, but make the color red, you can author the new style like this:"
<style name="AppTheme" parent="AppBaseTheme">
<item name="android:textColor">#fff</item>
<item name="android:textSize">12sp</item>
</style>
<style name="AppTheme.MainActivity">
<item name="android:textColor">#f0f</item>
<item name="android:background">@color/black</item>
</style>
and
<activity android:theme="@style/AppTheme.MainActivity"
...>
...
</activity>`