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);
}

.rail {
  position: relative;
  overflow: hidden;
  width: 200px;
  height: min(50vw, 150px);
  border-radius: 16px;
  background: #17141a;
  transform: scaleX(0.28);
  transform-origin: left center;
  transition: transform 300ms ease-out;
  cursor: pointer;
}

.rail__inner {
  width: 200px;
  height: 100%;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 16px 12px;
  transform: scaleX(3.5714285714);
  transform-origin: left center;
  transition: transform 300ms ease-out;
}

.rail__item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 8px;
  border-radius: 8px;
  color: #ffffff;
  text-decoration: none;
}
.rail__item:hover, .rail__item:focus-visible {
  background: rgba(255, 255, 255, 0.12);
}

.rail__ic {
  flex: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: #ffd23f;
}

.rail__label {
  font-weight: 500;
  font-size: 13px;
  line-height: 1;
  font-family: inherit;
  white-space: nowrap;
  opacity: 0.9;
}

.rail:hover, .rail:focus-within {
  transform: scaleX(1);
}
.rail:hover .rail__inner, .rail:focus-within .rail__inner {
  transform: scaleX(1);
}

.stage.is-demo .rail {
  animation: rail-loop 2s ease-out infinite;
}

.stage.is-demo .rail__inner {
  animation: rail-inner-loop 2s ease-out infinite;
}

@keyframes rail-loop {
  0%, 100% {
    transform: scaleX(0.28);
  }
  30%, 75% {
    transform: scaleX(1);
  }
}
@keyframes rail-inner-loop {
  0%, 100% {
    transform: scaleX(3.5714285714);
  }
  30%, 75% {
    transform: scaleX(1);
  }
}
@media (prefers-reduced-motion: reduce) {
  .stage.is-demo .rail, .stage.is-demo .rail__inner {
    animation: none;
  }
  .rail, .rail__inner {
    transition-duration: 1ms;
  }
}