1. Adding Script Editor Web Part to Course Catalog Home Page :
On the Course Catalog Home page click Edit Page -> Add a Web Part -> Media and Content -> Script Editor
2. Click Edit Snippet of Script Editor Web Part -> Embed Attached CSS file -> Insert and Apply changes.
3.On the screenshot below you can find the code part, where you are able to change colors. As an example, we use column 1.
Please, find the CSS file attached.