Invoice app solution using React, React Router, Styled Components

This is still a work in progress and not a final solution. The reason why I am submitting it as solution early is, because my Pro subscription ends tomorrow and I am not planning to extend it at this time.

Some notable things that I have yet to implement are: Theme Switcher, styling of the select element, desktop view styling to be inline with the design and tablet computers styling, some features for creating and editing an invoice and general code refactoring/cleanup. Also right now the code is all over the place with many unnecessary repetitions and is generally of low quality. The reason for this is because I had to rush with building this solution so that I could at least submit as solution something that at least basically works as intended. I could only work on this problem for about 9 days in the last 30 days, which is for me really short time to complete a project as complex as this one is.

The good news is that the reason why I was so busy in the last 30 days and I couldn't spend as much time on this project, is because I got an opportunity to build a web application with React that will end up actually being used by people on a day to day basis. Also, like I mentioned it did only take me about 9 days to create a somewhat passable solution, which I am somewhat proud of in a weird way.

If anyone has any feedback that is great, but I am not really expecting any. Like I said there is still a lot of work ahead of me, before I will be satisfied with this app and it will work and look as intended.

Lastly if anyone actually reads all this and is perhaps thinking of starting this challenge but you are worried that the challenge is too complex for you, I recommend you first complete the REST Countries API challenge and the Todo app challenge. I found that completing both of this challenges before was quite helpful with working on this project and was probably the main reason why I could actually create a somewhat passable solution in such a short time for me.

Thanks for anyone who read this or has any feedback for me.