I can't find what I am missing

Hi campers! sending SOS from South Korea.
I’m doing my last project of front-end libraries (I can’t believe it!), ’ Pomodoro Clock’
It’s fun. I was excited to imply ‘setInterval’ method on React to make my clock tic and toc.
However, somehow my clock isn’t working and even show up. I think I missed something but I couldn’t find it.
If anybody kindly look on my codes and find something wrong, I will be more than happy for that! If you want to suggest any other way to solve this project’s test / problem please feel free to give me an advice or two!

Thank you in advance.

This is my link : https://codepen.io/atiktook/pen/vYGYwrw?editors=0011

I don’t have time to go through your code at the moment but open the JS console and then click on the Stop button. I think you’ll see an error message that could be helpful.