:root {
  --bg-a: #0b1b2d;
  --bg-b: #07131e;
  --bg-c: #194264;
  --text: #f2f8ff;
  --accent: #8cd7ff;
  --panel-bg: rgba(4, 10, 20, 0.5);
  --panel-border: rgba(255, 255, 255, 0.22);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  width: 100%;
  height: 100%;
}

body {
  overflow: hidden;
  color: var(--text);
  font-family: "Segoe UI", "Noto Sans KR", "Apple SD Gothic Neo", sans-serif;
  background:
    radial-gradient(circle at 16% 18%, var(--bg-c), transparent 40%),
    linear-gradient(135deg, var(--bg-a), var(--bg-b));
}

#scene {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  touch-action: none;
}

.overlay {
  position: fixed;
  top: 1rem;
  left: 1rem;
  z-index: 2;
  width: min(320px, calc(100% - 2rem));
  display: grid;
  gap: 0.55rem;
  padding: 0.95rem;
  border-radius: 14px;
  border: 1px solid var(--panel-border);
  background: var(--panel-bg);
  backdrop-filter: blur(10px);
}

h1 {
  margin: 0 0 0.2rem;
  font-size: 1rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  line-height: 1.35;
}

label {
  font-size: 0.8rem;
  opacity: 0.92;
}

select {
  width: 100%;
  border: 1px solid rgba(255, 255, 255, 0.26);
  border-radius: 8px;
  padding: 0.45rem 0.55rem;
  color: var(--text);
  background: rgba(0, 0, 0, 0.24);
}

.desc {
  margin: 0.12rem 0 0.08rem;
  font-size: 0.86rem;
  line-height: 1.4;
  color: rgba(242, 248, 255, 0.9);
}

.toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.84rem;
}

.toggle input {
  margin: 0;
  accent-color: var(--accent);
}

@media (max-width: 640px) {
  .overlay {
    top: auto;
    bottom: 1rem;
  }
}