CSS 요소 숨기기

1. display

: display: none <-> display: block
-> 차지하던 공간까지 사라짐

2. visibility

: visibility: hidden <-> visibility: visible
-> 차지하던 공간은 그대로 유지되고 컨텐츠만 숨겨짐

참고자료
https://m.blog.naver.com/PostView.naver?isHttpsRedirect=true&blogId=minjung2623&logNo=221222987993
https://dreamzelkova.tistory.com/entry/CSS-display-visivility-%EB%B3%B4%EC%9D%B4%EA%B8%B0-%EC%88%A8%EA%B8%B0%EA%B8%B0-%EC%9D%B8%EB%9D%BC%EC%9D%B8-%EB%B8%94%EB%9F%AD