<ボタンcss>
https://deshinon.com/2019/03/02/simple-button-css/
https://jajaaan.co.jp/css/button/

< firebase >
https://firebase.google.com/docs/firestore/manage-data/add-data#web-v8 (document名)
https://qiita.com/yuiken/items/1a43a2a87ca421626f18 (timestamp)

< React >
https://ja.reactjs.org/docs/forms.html
https://ja.reactjs.org/docs/hooks-state.html

< cloneしたらnpm start できなかった >
https://itsakura.com/react-hello
https://qiita.com/wafuwafu13/items/2fe43414aa6e1899f494

<nodeとpackage.json>
https://qiita.com/righteous/items/e5448cb2e7e11ab7d477