border에 그라디언트 넣기
border-top: 3px solid transparent; border-image: linear-gradient(90deg, rgba(253,29,29,1) 0%, rgba(252,176,69,1) 30%, rgba(142,255,121,1) 64%, rgba(131,58,180,1) 100%) 1; background-origin: border-box; background-clip: content-box, border-box; background: #fff; border-image의 맨끝 1은 꼭 넣기 둥글기가 들어가있으면 적용되지 않음