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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #17141a;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.wrap {
  position: relative;
  width: clamp(200px, 72%, 300px);
  display: grid;
}

.card {
  grid-area: 1/1;
  padding: clamp(14px, 4vw, 18px);
  border-radius: 16px;
  display: grid;
  gap: clamp(8px, 2.6vw, 10px);
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}

.bar {
  height: clamp(11px, 3.2vw, 14px);
  border-radius: 12px;
  width: 85%;
}

.bar.short {
  width: 55%;
}

.card.light {
  background: #ffffff;
  animation: swap-out 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}
.card.light .bar {
  background: rgba(23, 20, 26, 0.16);
}

.card.dark {
  background: #17141a;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32), inset 0 0 0 1px rgba(255, 247, 230, 0.14);
  animation: swap-in 2s cubic-bezier(0.2, 0.8, 0.2, 1) infinite;
}
.card.dark .bar {
  background: rgba(255, 247, 230, 0.22);
}

@keyframes swap-out {
  0% {
    opacity: 1;
  }
  50% {
    opacity: 0;
  }
  100% {
    opacity: 1;
  }
}
@keyframes swap-in {
  0% {
    opacity: 0;
  }
  50% {
    opacity: 1;
  }
  100% {
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .card.light {
    animation: none !important;
    opacity: 0;
  }
  .card.dark {
    animation: none !important;
    opacity: 1;
  }
}