How can I change the background in my phone contacts app?

Episode 1220
Gary fromGary just updated to the Samsung Galaxy Note 4 and he likes that he can use a spare button. Leo says that every time he would get a new Note in the past, he would buy extra batteries. He also likes the additional SD card slot for storage. Both are very nice features. Gary loves the Note 4 except for one thing -- when he goes into the contact page, the background color is white, making it harder to see the areas to enter data. Can he change that? Leo says that Samsung may have a dark theme. He should look in the settings for theming capabilities, and change it there.