Mobile first, flex-box, react

Lighthouse gives this a really bad score on optimization because I use unpkg to get react and babel but actually npm this for a project like this seems a real overkill since you get so many MB in the node_modules folder when this whole thing takes up like 500kb on my drive. So is this a legit practice in this scope of a project?

The way I use components? Ok for this scope?

My flexbox solution, works but should I have given more thought to scaleability and flexibility?