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);
}

.fg {
  position: relative;
  width: min(240px, 82vw);
}

.fg__input {
  box-sizing: border-box;
  width: 100%;
  border: 2px solid rgba(255, 247, 230, 0.4);
  border-radius: 12px;
  padding: 16px 16px;
  font-weight: 500;
  font-size: clamp(14px, 4vw, 16px);
  line-height: 1;
  font-family: inherit;
  color: #fff7e6;
  background: transparent;
  position: relative;
  z-index: 1;
}
.fg__input:focus {
  outline: none;
}

.fg__glow {
  position: absolute;
  inset: -8px;
  border-radius: 16px;
  border: 2px solid #fff7e6;
  opacity: 0;
  transform: scale(0.92);
  pointer-events: none;
}

.fg:has(.fg__input:focus) .fg__glow {
  animation: glow-in 300ms cubic-bezier(0.3, 1.6, 0.4, 1) both, glow-pulse 2s ease-out 300ms infinite;
}

@keyframes glow-in {
  0% {
    opacity: 0;
    transform: scale(0.8);
  }
  60% {
    opacity: 0.95;
    transform: scale(1.08);
  }
  100% {
    opacity: 0.35;
    transform: scale(0.92);
  }
}
@keyframes glow-pulse {
  0%, 100% {
    opacity: 0.35;
    transform: scale(0.92);
  }
  50% {
    opacity: 0.9;
    transform: scale(1.04);
  }
}
@media (prefers-reduced-motion: reduce) {
  .fg:has(.fg__input:focus) .fg__glow {
    animation: none;
    opacity: 0.7;
    transform: scale(1);
  }
}