* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  background: #f2f2f2;
  background-color: black;
}
.noto-sans-kr {
  font-family: "Noto Sans KR", sans-serif;
  font-optical-sizing: auto;
  font-weight: 400;
  font-style: normal;
}
section {
  overflow: hidden;
  width: 100%;
  height: 100vh;
  position: relative;
}
/* home */
.home_title {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
.home_title h1 {
  font-family: "Noto Sans KR", sans-serif;
  line-height: 4rem;
}
/* btn */
.btn_start {
  position: relative;
  z-index: 1;
}
.btn_start::after {
  content: "";
  z-index: -1;
  position: absolute;
  width: 100%;
  height: 100%;
  background-color: black;
  border-radius: 25px;
  left: 0;
  top: 0;
}
.btn_start::before {
  content: "";
  background: linear-gradient(45deg, #d785f0, #6c2ab8);
  position: absolute;
  top: -2px;
  left: -2px;
  background-size: 600%;
  z-index: -1;
  width: calc(100% + 4px);
  height: calc(100% + 4px);
  filter: blur(8px);
  /* animation */
  animation: glowing 10s linear infinite;
  transition: opacity 0.3s ease-in-out;
  opacity: 1;
}
@keyframes glowing {
  0% {
    background-position: 0 0;
  }
  50% {
    background-position: 150% 0;
  }
  100% {
    background-position: 0 0;
  }
}
/* hover */
.btn_start:hover::before {
  opacity: 1;
}
.btn_start:hover::after {
  background: transparent;
}
/* 무한 이미지 슬라이딩 */
@keyframes slide {
  from {
    transform: translateY(0%);
  }
  to {
    transform: translateY(-50%);
  }
}

.card_container {
  display: flex;
  flex-direction: column;
  margin: auto;
  padding: 10px;
}
.card_slide {
  display: inline-block;
  /* 애니메이션 적용 */
  animation: 250s slide infinite linear 0s;
}
.card_slide:nth-child(odd) {
  animation-name: slide;
  animation-direction: reverse;
}
.card_containers {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  column-gap: 3.5rem;
  position: relative;
}
/* 태블릿 화면에서 3개 열 */
@media only screen and (max-width: 1024px) {
  .card_containers {
    grid-template-columns: repeat(3, 1fr);
    column-gap: 1rem;
  }
}
/* 모바일 화면에서 2개 열 */
@media only screen and (max-width: 768px) {
  .card_containers {
    grid-template-columns: repeat(2, 1fr);
    column-gap: 2rem;
  }
}
.card_container::before,
.card_containers::after {
  position: absolute;
  left: 0;
  width: 100%;
  height: 250px;
  content: "";
  z-index: 2;
}
.card_containers::before {
  top: 0;
  background: linear-gradient(to top, rgba(255, 255, 255, 0), black);
}
.card_containers::after {
  bottom: 0;
  background: linear-gradient(to bottom, rgba(255, 255, 255, 0), black);
}
/* image size */
.card_container .card_item {
  width: 200px;
  height: 300px;
  margin: 2.5rem 0;
  opacity: 0.6;
}