Apply custom theme to the header of the navigation drawer.

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

@@ -1,9 +0,0 @@
-<shape xmlns:android="http://schemas.android.com/apk/res/android"
-    android:shape="rectangle">
-    <gradient
-        android:angle="135"
-        android:centerColor="#0336FF"
-        android:endColor="#002BF0"
-        android:startColor="#5954FF"
-        android:type="linear" />
-</shape>

app/src/main/res/layout/nav_header_main.xml

@@ -2,7 +2,6 @@
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="@dimen/nav_header_height"
-    android:background="@drawable/side_nav_bar"
     android:gravity="bottom"
     android:orientation="vertical"
     android:theme="@style/ThemeOverlay.AppCompat.Dark">
@@ -11,7 +10,7 @@
         android:id="@+id/banner_image_view_nav_header_main"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        android:scaleType="centerCrop"/>
+        android:scaleType="centerCrop" />
 
     <pl.droidsonroids.gif.GifImageView
         android:id="@+id/profile_image_view_nav_header_main"
@@ -20,7 +19,7 @@
         android:layout_marginTop="40dp"
         android:layout_marginBottom="16dp"
         android:layout_marginStart="16dp"
-        android:layout_marginEnd="16dp"/>
+        android:layout_marginEnd="16dp" />
 
     <TextView
         android:id="@+id/name_text_view_nav_header_main"
@@ -30,7 +29,6 @@
         android:layout_marginStart="16dp"
         android:layout_marginEnd="16dp"
         android:layout_alignParentStart="true"
-        android:textAppearance="@style/TextAppearance.AppCompat.Body1"
         android:textSize="?attr/font_default"
         android:fontFamily="?attr/font_family"
         android:layout_below="@id/profile_image_view_nav_header_main"