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

.stage {
  box-sizing: border-box;
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ff4d1f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
  padding: clamp(8px, 4vw, 24px);
}

.stage {
  padding: clamp(6px, 2.4vw, 16px);
}

.btn {
  position: relative;
  border: 0;
  border-radius: 999px;
  padding: 14px 30px;
  font-weight: 700;
  font-size: clamp(13px, 3.6vw, 15px);
  line-height: 1;
  font-family: inherit;
  color: #17141a;
  background: #fff7e6;
  cursor: pointer;
  box-shadow: 0 0 0 3px rgba(255, 247, 230, 0.9);
}

.btn::after {
  content: "";
  position: absolute;
  inset: -3px;
  border-radius: inherit;
  border: 2px solid #fff7e6;
  opacity: 0;
  transform: scale(1);
  transition: transform 300ms ease-out, opacity 300ms ease-out;
}

.btn:hover::after, .btn:focus-visible::after {
  opacity: 1;
  transform: scale(1.3);
}

.btn.is-demo::after {
  animation: ring-pulse 2s ease-out infinite;
}

@keyframes ring-pulse {
  0%, 15% {
    transform: scale(1);
    opacity: 0.9;
  }
  70% {
    transform: scale(1.35);
    opacity: 0;
  }
  100% {
    transform: scale(1.35);
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .btn::after {
    transition: none;
  }
  .btn.is-demo::after {
    animation: none;
    opacity: 0;
  }
}