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);
}

.bubble {
  padding: 22px 34px;
  border-radius: 16px;
  background: #fff7e6;
  color: #17141a;
  font-weight: 700;
  font-size: clamp(18px, 5.6vw, 24px);
  line-height: 1.4;
  font-family: inherit;
  transform-origin: center;
}
.bubble.is-demo {
  animation: bubble-pop-loop 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

@keyframes bubble-pop-loop {
  0% {
    transform: scale(0.4);
    opacity: 0;
  }
  16% {
    transform: scale(1.15);
    opacity: 1;
  }
  24% {
    transform: scale(1);
    opacity: 1;
  }
  82% {
    transform: scale(1);
    opacity: 1;
  }
  100% {
    transform: scale(0.4);
    opacity: 0;
  }
}
@media (prefers-reduced-motion: reduce) {
  .bubble.is-demo {
    animation: none !important;
    transform: none;
    opacity: 1;
  }
}