You specify the colors for two different types of text in the ShowTime theme. The image above should help you understand the difference between these two settings. The Content heading and text options pertain to text that shows outside the white container boxes. This includes things like the page title, breadcrumb, and some elements on the home page. The color you choose here should contrast with your chosen background color.
The other heading and text options pertain to text that shows within the white content containers.