Health Center Theme comes with 8 preset colors and some background pattern . You can create your own color theme using the color picker. You can find this setting in Theme Appearance Customize. You have to no need any code customization. In this theme we just want to offer visitors color variations. Now I will tell you how to change color schemes? Do following tutorial. Refer attach screen shot.
1. How to Change Theme Color Scheme?
Go to => WP-Menu => Appearance => Customize => Theme Color Schemes Settings
Here you can see the Predefined Color Schemes, Custom Skin Color and Background Patterns. There are 8 Predefined colors in this theme. Refer attach screen shot.