archy/Android/app/src/main/res/drawable/ic_launcher_background.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- Dark fill + the badge's metallic ring. The ring is scaled to ~0.68 so it
     lands inside the adaptive-icon safe zone (the outer ~18dp is cropped by the
     launcher) and reads at the edge of the visible circle. Brightened
     grey->white so it's clearly visible on #0A0A0A. -->
<vector xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:aapt="http://schemas.android.com/aapt"
    android:width="108dp"
    android:height="108dp"
    android:viewportWidth="752"
    android:viewportHeight="752">

    <path
        android:fillColor="#0A0A0A"
        android:pathData="M0,0h752v752H0z" />

    <group
        android:pivotX="376"
        android:pivotY="376"
        android:scaleX="0.68"
        android:scaleY="0.68">
        <path
            android:fillColor="#0A0A0A"
            android:strokeWidth="26"
            android:pathData="M11.441,375.669a364.227,364.227 0 1,0 728.454,0a364.227,364.227 0 1,0 -728.454,0z">
            <aapt:attr name="android:strokeColor">
                <gradient
                    android:type="linear"
                    android:startX="751.337"
                    android:startY="751.338"
                    android:endX="0"
                    android:endY="0">
                    <item android:offset="0" android:color="#FF777777" />
                    <item android:offset="1" android:color="#FFFFFFFF" />
                </gradient>
            </aapt:attr>
        </path>
    </group>
</vector>