replicant-vendor_replicant/overlay/common/packages/apps/ExactCalculator/res/values/styles.xml

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

    <style name="Theme" parent="@android:style/Theme.Material.Light.DarkActionBar">
        <item name="android:colorPrimary">#ff212121</item>
        <item name="android:statusBarColor">#fff</item>
        <item name="android:windowSoftInputMode">stateAlwaysHidden</item>
        <item name="android:windowLightStatusBar">true</item>
        <item name="android:navigationBarColor">#ff212121</item>
    </style>

</resources>