https://unikys.tistory.com/333
https://blog.naver.com/PostView.naver?blogId=wnsrhkqja&logNo=221411967642
->animation 속성 사용법
https://blogpack.tistory.com/882
->animation 속성 사용법
https://blog.naver.com/wnsrhkqja/221403191783
->transition 속성 사용법
https://homzzang.com/b/css-171
@keyframe 사용법
https://www.daleseo.com/css-position-absolute/
position, top, left, right 등등 사용법
https://www.zerocho.com/category/CSS/post/5864f3b59f1dc000182d3ea1
css positon 옵션 사용법
https://ossam5.tistory.com/226
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