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);
}

.sf-viewport {
  width: min(300px, 88vw);
  height: 170px;
  overflow: hidden;
  box-sizing: border-box;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  -webkit-mask-image: linear-gradient(to bottom, transparent 0, #000 32px, #000 calc(100% - 32px), transparent 100%);
  mask-image: linear-gradient(to bottom, transparent 0, #000 32px, #000 calc(100% - 32px), transparent 100%);
  padding: 16px 0;
}

.sf-track {
  display: flex;
  flex-direction: column;
}

.sf-msg {
  padding: 8px 16px;
  margin: 0 16px 8px;
  border-radius: 8px;
  background: rgba(23, 20, 26, 0.06);
  color: #17141a;
  font: 500 12px/1.4 -apple-system, "Segoe UI", sans-serif;
}

@keyframes sf-scroll {
  from {
    transform: translateY(0);
  }
  to {
    transform: translateY(-50%);
  }
}
.sf-track.is-demo {
  animation: sf-scroll 6s linear infinite;
}

@media (prefers-reduced-motion: reduce) {
  .sf-track.is-demo {
    animation: none !important;
    transform: none !important;
  }
}