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);
}

.track {
  position: relative;
  width: 220px;
  height: 8px;
}

.dot {
  position: absolute;
  top: 50%;
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.25);
  transform: translate(-50%, -50%);
}

.dot--start {
  left: 0;
}

.dot--end {
  left: 220px;
}

.puck {
  position: absolute;
  top: 50%;
  left: 0;
  width: 24px;
  height: 24px;
  border-radius: 999px;
  background: #2f6df6;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  transform: translate(0, -50%);
}

.stage.is-demo .puck {
  animation: move 2s cubic-bezier(0.25, 1, 0.5, 1) infinite alternate;
}

@keyframes move {
  from {
    transform: translate(0, -50%);
  }
  to {
    transform: translate(196px, -50%);
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .puck {
    animation: none;
    transform: translate(196px, -50%);
  }
}