pinia, 반응형, Refs 사용법 참조
[pinia] https://velog.io/@eggplantiny/Pinia-Vuex-를-대체할-새로운-Store
[반응형] https://v3.ko.vuejs.org/guide/reactivity-fundamentals.html#반응형-상태-구조-분해하기-destructuring
[Refs] https://v3.ko.vuejs.org/api/refs-api.html#ref