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);
}

.pi {
  width: min(280px, 84vw);
}

.pi__radio {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.pi__nav {
  position: relative;
  isolation: isolate;
  display: flex;
  gap: 8px;
  padding: 4px;
  background: rgba(23, 20, 26, 0.08);
  border-radius: 999px;
}

.pi__tab {
  position: relative;
  z-index: 1;
  flex: 0 0 auto;
  text-align: center;
  padding: 8px 4px;
  font-weight: 600;
  font-size: clamp(12px, 3.4vw, 14px);
  line-height: 1;
  font-family: inherit;
  color: #17141a;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.pi__pill {
  position: absolute;
  top: 4px;
  left: 4px;
  bottom: 4px;
  width: 37px;
  border-radius: 999px;
  background: #0a4fe8;
  transform: translateX(0) scaleX(1);
  transform-origin: left center;
  transition: transform 220ms cubic-bezier(0.2, 1.4, 0.4, 1);
}

.pi__nav::after {
  content: "";
  position: absolute;
  top: 4px;
  left: 4px;
  bottom: 4px;
  z-index: -1;
  width: 37px;
  border-radius: 999px;
  background: rgba(10, 79, 232, 0.3);
  filter: blur(2px);
  transform: translateX(0) scaleX(1);
  transform-origin: left center;
  opacity: 0;
}

#pi-1:checked ~ .pi__nav .pi__pill {
  transform: translateX(0) scaleX(1);
}

#pi-2:checked ~ .pi__nav .pi__pill {
  transform: translateX(calc(37px + 8px)) scaleX(1.405);
}

#pi-3:checked ~ .pi__nav .pi__pill {
  transform: translateX(calc(37px + 52px + 8px * 2)) scaleX(1);
}

#pi-1:checked ~ .pi__nav label[for=pi-1],
#pi-2:checked ~ .pi__nav label[for=pi-2],
#pi-3:checked ~ .pi__nav label[for=pi-3] {
  color: #fff7e6;
}

.pi.is-demo .pi__pill {
  animation: pi-loop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.pi.is-demo .pi__nav::after {
  animation: pi-trail-loop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
  animation-delay: 120ms;
}

.pi.is-demo .pi__nav label[for=pi-1] {
  animation: pi-ink-1 2s linear infinite;
}

.pi.is-demo .pi__nav label[for=pi-2] {
  animation: pi-ink-2 2s linear infinite;
}

.pi.is-demo .pi__nav label[for=pi-3] {
  animation: pi-ink-3 2s linear infinite;
}

@keyframes pi-ink-1 {
  0%, 15% {
    color: #fff7e6;
  }
  23%, 87% {
    color: #17141a;
  }
  95%, 100% {
    color: #fff7e6;
  }
}
@keyframes pi-ink-2 {
  0%, 25% {
    color: #17141a;
  }
  33%, 48% {
    color: #fff7e6;
  }
  56%, 100% {
    color: #17141a;
  }
}
@keyframes pi-ink-3 {
  0%, 58% {
    color: #17141a;
  }
  66%, 81% {
    color: #fff7e6;
  }
  89%, 100% {
    color: #17141a;
  }
}
@keyframes pi-loop {
  0%, 15% {
    transform: translateX(0) scaleX(1);
  }
  30% {
    transform: translateX(calc(37px + 8px + 5px)) scaleX(1.405);
  }
  33%, 48% {
    transform: translateX(calc(37px + 8px)) scaleX(1.405);
  }
  63% {
    transform: translateX(calc(37px + 52px + 8px * 2 + 5px)) scaleX(1);
  }
  66%, 81% {
    transform: translateX(calc(37px + 52px + 8px * 2)) scaleX(1);
  }
  96% {
    transform: translateX(-5px) scaleX(1);
  }
  100% {
    transform: translateX(0) scaleX(1);
  }
}
@keyframes pi-trail-loop {
  0%, 15% {
    transform: translateX(0) scaleX(1);
    opacity: 0;
  }
  24% {
    opacity: 0.3;
  }
  30% {
    transform: translateX(calc(37px + 8px + 5px)) scaleX(1.405);
    opacity: 0.3;
  }
  33%, 40% {
    transform: translateX(calc(37px + 8px)) scaleX(1.405);
    opacity: 0.3;
  }
  48% {
    transform: translateX(calc(37px + 8px)) scaleX(1.405);
    opacity: 0;
  }
  63% {
    transform: translateX(calc(37px + 52px + 8px * 2 + 5px)) scaleX(1);
    opacity: 0.3;
  }
  66%, 73% {
    transform: translateX(calc(37px + 52px + 8px * 2)) scaleX(1);
    opacity: 0.3;
  }
  81% {
    transform: translateX(calc(37px + 52px + 8px * 2)) scaleX(1);
    opacity: 0;
  }
  100% {
    transform: translateX(0) scaleX(1);
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .pi__pill {
    transition: none;
  }
  .pi.is-demo .pi__pill,
  .pi.is-demo .pi__nav::after {
    animation: none !important;
  }
  .pi.is-demo .pi__nav label {
    animation: none !important;
  }
  .pi__nav::after {
    opacity: 0;
  }
}