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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.track {
  position: relative;
  width: clamp(200px, 58vw, 280px);
  height: 8px;
  border-radius: 999px;
  background: rgba(23, 20, 26, 0.12);
  overflow: hidden;
}

.seg {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: #17141a;
  transform-origin: left center;
}

.seg--a.is-demo {
  animation: seg-a 1.6s cubic-bezier(0.4, 0, 0.2, 1) infinite;
}

.seg--b.is-demo {
  animation: seg-b 1.6s cubic-bezier(0.4, 0, 0.2, 1) infinite;
  animation-delay: 0.56s;
}

@keyframes seg-a {
  0% {
    transform: translateX(-100%) scaleX(0.15);
  }
  55% {
    transform: translateX(30%) scaleX(0.7);
  }
  100% {
    transform: translateX(120%) scaleX(0.15);
  }
}
@keyframes seg-b {
  0% {
    transform: translateX(-140%) scaleX(0.1);
  }
  60% {
    transform: translateX(10%) scaleX(0.4);
  }
  100% {
    transform: translateX(120%) scaleX(0.1);
  }
}
.cap {
  margin: 14px 0 0;
  color: rgba(23, 20, 26, 0.75);
  font: 600 clamp(12px, 3.2vw, 14px)/1 -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

@media (prefers-reduced-motion: reduce) {
  .seg.is-demo {
    animation: none;
    transform: translateX(0) scaleX(0.4);
    opacity: 0.7;
  }
}