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);
}

.panel {
  position: relative;
  overflow: hidden;
  width: clamp(200px, 70vw, 260px);
  height: clamp(120px, 42vw, 150px);
  border-radius: 16px;
  box-shadow: 0 14px 24px rgba(23, 20, 26, 0.32);
  background: #fff7e6;
  color: #17141a;
  box-sizing: border-box;
  padding: clamp(12px, 5vw, 18px);
  text-align: left;
}

.panel__title {
  margin: 0 0 6px;
  font-weight: 700;
  font-size: clamp(12px, 3.6vw, 15px);
  line-height: 1.3;
  font-family: inherit;
}

.panel__line {
  margin: 0;
  width: 55%;
  height: 8px;
  border-radius: 4px;
  background: currentColor;
  opacity: 0.25;
}

.icon {
  position: absolute;
  top: clamp(10px, 4vw, 16px);
  right: clamp(10px, 4vw, 16px);
  width: 34px;
  height: 34px;
}

.icon__core {
  position: absolute;
  inset: 6px;
  border-radius: 50%;
}

.icon__core--sun {
  background: #ffd23f;
  opacity: 1;
  animation: core-light 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.icon__core--moon {
  background: #17141a;
  opacity: 0;
  animation: core-dark 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

.icon__ray {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 3px;
  height: 8px;
  border-radius: 2px;
  background: #ffd23f;
  transform-origin: 50% 17px;
  transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(1);
  animation: ray-fold 2s cubic-bezier(0.2, 1.4, 0.4, 1) infinite;
}

@keyframes core-light {
  0%, 15% {
    opacity: 1;
  }
  40%, 60% {
    opacity: 0;
  }
  85%, 100% {
    opacity: 1;
  }
}
@keyframes core-dark {
  0%, 15% {
    opacity: 0;
  }
  40%, 60% {
    opacity: 1;
  }
  85%, 100% {
    opacity: 0;
  }
}
@keyframes ray-fold {
  0%, 15% {
    opacity: 1;
    transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(1);
  }
  40%, 60% {
    opacity: 0;
    transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(0);
  }
  85%, 100% {
    opacity: 1;
    transform: rotate(calc(var(--i) * 60deg)) translateY(-17px) scaleY(1);
  }
}
@media (prefers-reduced-motion: reduce) {
  .icon__core--sun, .icon__core--moon, .icon__ray {
    animation: none !important;
  }
}