Rest Countries API with Angular, Interceptor, Fallback Data

In this project i really improved my angular skills from newbie to intermediate, i would claim. I made use of interceptors, to set a loading spinner while requesting th apis, and worked with interfaces to use the data from the api response. It was really headache but fun. I still got two main issues, which i'm currently not able to fix. The text color of the theme switcher appears wrong and the values for a method are undefined after manually reloading the component (documented in github). Any advice how to fix these issues are welcome! :)