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

.stage {
  min-height: 100vh;
  display: grid;
  place-items: center;
  margin: 0;
  background: #ffd23f;
  font-family: -apple-system, "Segoe UI", "Noto Sans KR", sans-serif;
}

.btn {
  border: 0;
  border-radius: 14px;
  padding: 22px 56px;
  font: 800 20px/1 inherit;
  color: #fff7e6;
  background: #17141a;
  cursor: pointer;
  will-change: transform;
  transition: transform 220ms cubic-bezier(0.2, 0.8, 0.2, 1), box-shadow 220ms;
}
.btn:hover, .btn:focus-visible {
  transform: translateY(-6px);
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
}
.btn:active {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(23, 20, 26, 0.32);
}
.btn.is-demo {
  animation: lift-loop 2s ease-in-out infinite;
}

@keyframes lift-loop {
  0%, 15% {
    transform: translateY(0);
    box-shadow: 0 0 0 rgba(23, 20, 26, 0);
  }
  45%, 70% {
    transform: translateY(-6px);
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
  100% {
    transform: translateY(0);
    box-shadow: 0 0 0 rgba(23, 20, 26, 0);
  }
}
@media (prefers-reduced-motion: reduce) {
  .btn, .btn.is-demo {
    transition: none;
    animation: none;
  }
  .btn:hover {
    box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  }
}