HealthDiary/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="#0043FD"
        android:endColor="@color/colorAccent"
        android:startColor="@color/colorAccent"
        android:type="linear" />
</shape>