I'm looking for feedback on my React code and anything else that stands out (good or bad).

This is another refactored project. I submitted a HTML/CSS/JS solution last year.

I am revising my earlier html/css challenges using React and Styled Components.

Even if you're not familiar with React, you can make sense of the CSS here because Styled Components uses regular CSS code.

I am interested in any and all feedback. Specifically:

• How's my component code look? (JSX, PropTypes, naming, etc)
• Do I need to improve my CSS rules? I've used REM everywhere except the media query and when vw worked better.
• What's your impression of my readme? Too long? Not detailed enough? I'd like it to be useful for FEM members thinking about moving from html/css to React.

Thanks in advance! Aaron

👋 I will be updating this app (refactoring state using Redux, writing more tests), so I am interested in any and all feedback!

• The timer mode is controlled by a form containing three radio inputs. There's no submit button because the form is never meant to be submitted. What's the best approach to this accessibility issue?
• Why is Firefox rendering my colors differently than Chrome/Safari?
• Is there too much transition bling on the buttons?