html, body {
  margin: 0;
  overflow: hidden;
}

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffffff;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.kb {
  width: min(360px, 80vw);
}

.kb__stage {
  display: grid;
  aspect-ratio: 16/10;
  border-radius: 16px;
  overflow: hidden;
}

.kb__card {
  grid-area: 1/1;
  overflow: hidden;
}

.kb__img {
  width: 100%;
  height: 100%;
}

.kb__img--1 {
  background: radial-gradient(120% 120% at 30% 20%, #2f6df6, #14264d);
}

.kb__img--2 {
  background: radial-gradient(120% 120% at 70% 30%, #ff4d1f, #4a1c0d);
}

.kb__img--3 {
  background: radial-gradient(120% 120% at 50% 70%, #c2ae82, #3a2a05);
}

.kb__card--1 {
  animation: kb-fade-1 2s linear infinite;
}

.kb__card--2 {
  animation: kb-fade-2 2s linear infinite;
}

.kb__card--3 {
  animation: kb-fade-3 2s linear infinite;
}

.kb__img--1 {
  animation: kb-zoom-1 2s ease-out infinite;
}

.kb__img--2 {
  animation: kb-zoom-2 2s ease-out infinite;
}

.kb__img--3 {
  animation: kb-zoom-3 2s ease-out infinite;
}

@keyframes kb-fade-1 {
  0% {
    opacity: 0;
  }
  12%, 25% {
    opacity: 1;
  }
  37%, 100% {
    opacity: 0;
  }
}
@keyframes kb-fade-2 {
  0%, 25% {
    opacity: 0;
  }
  37%, 58% {
    opacity: 1;
  }
  70%, 100% {
    opacity: 0;
  }
}
@keyframes kb-fade-3 {
  0%, 58% {
    opacity: 0;
  }
  70%, 88% {
    opacity: 1;
  }
  100% {
    opacity: 0;
  }
}
@keyframes kb-zoom-1 {
  0% {
    transform: scale(1);
  }
  29% {
    transform: scale(1.16);
  }
  29.1%, 100% {
    transform: scale(1);
  }
}
@keyframes kb-zoom-2 {
  0%, 33% {
    transform: scale(1);
  }
  62% {
    transform: scale(1.16);
  }
  62.1%, 100% {
    transform: scale(1);
  }
}
@keyframes kb-zoom-3 {
  0%, 66% {
    transform: scale(1);
  }
  96% {
    transform: scale(1.16);
  }
}
@media (prefers-reduced-motion: reduce) {
  .kb__card, .kb__img {
    animation: none !important;
  }
  .kb__card--1 {
    opacity: 1;
  }
  .kb__card--2, .kb__card--3 {
    opacity: 0;
  }
}