modify a theme and edit AndroidManifest.xml : question

[Khaled Designer]

Hello

i tried thunkable and i like the theme and than i search how to change theme of applications created by appinventor

i find many threads about apk tool , AI-Manifest-Editor ... but the problem that the AndroidManifest.xml didn't have anything about theme just a few lines

and other  AndroidManifest.xml in folder called original was crypted 

is there anymethod to modify the theme ?

[Taifun]

Material Theme by Boban

Taifun

---

Trying to push the limits of App Inventor! Snippets, Tutorials and Extensions from Pura Vida Apps by Taifun. 

[Khaled Designer]

thanks i see this blog nut no tool work for me 
the androidmanifest is like that 

<?xml version="1.0" encoding="utf-8" standalone="no"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android" package="package_name" platformBuildVersionCode="22" platformBuildVersionName="5.1.1-1819727">

<uses-permission android:name="android.permission.INTERNET"/>

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

<application android:debuggable="false" android:icon="@drawable/ya" android:label="Find a Day V2" android:name="apk_name">

<activity android:configChanges="keyboard|keyboardHidden|orientation" android:name="appinventor.ai_name" android:windowSoftInputMode="stateHidden">

<intent-filter>

<action android:name="android.intent.action.MAIN"/>

<category android:name="android.intent.category.LAUNCHER"/>

</intent-filter>

</activity>

</application>

</manifest>

nothing here about theme!
how i can add theme before recompile the apk ?