Define new letterbox background color

<?xml version="1.0" encoding="utf-8"?>

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<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:color="@color/system_neutral1_500" android:lStar="5" />

</selector>

            but isn't supported on the device or both dark scrim alpha and blur radius aren't

            provided.

     -->

    <color name="config_letterboxBackgroundColor">@android:color/system_neutral2_900</color>

    <color name="config_letterboxBackgroundColor">@color/letterbox_background</color>

    <!-- Horizontal position of a center of the letterboxed app window.

        0 corresponds to the left side of the screen and 1 to the right side. If given value < 0