Tweak tab indicator style

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

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android">
+    <corners
+        android:topLeftRadius="4dp"
+        android:topRightRadius="4dp" />
+    <solid android:color="?attr/colorOnPrimary" />
+</shape>

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

@@ -29,6 +29,9 @@
                 android:layout_width="match_parent"
                 android:layout_height="wrap_content"
                 app:tabGravity="center"
+                app:tabIndicator="@drawable/tab_indicator"
+                app:tabIndicatorFullWidth="false"
+                app:tabIndicatorHeight="3dp"
                 app:tabInlineLabel="true"
                 app:tabMinWidth="75dp"
                 app:tabMode="scrollable" />