packages/local_auth/local_auth_android/android/src/main/res/values/styles.xml

<resources>
  <!-- Fingerprint dialog theme. -->
  <style name="AlertDialogCustom" parent="@android:style/Theme.Material.Dialog.Alert">
    <item name="android:background">#FFFFFFFF</item>
    <item name="android:textStyle">bold</item>
    <item name="android:textSize">14sp</item>
    <item name="android:colorAccent">#FF009688</item>
  </style>
</resources>