Reisaye/app/src/main/res/drawable/side_nav_bar.xml

<shape xmlns:android="http://schemas.android.com/apk/res/android"
       android:shape="rectangle">
    <gradient
            android:angle="135"
            android:centerColor="#009688"
            android:endColor="#00695C"
            android:startColor="#4DB6AC"
            android:type="linear"/>
</shape>