:root {
  --bg-top: #0b1020;
  --bg-bottom: #1a2540;
  --text: #f4f6fb;
  --muted: #aab3c5;
  --panel: rgba(10, 14, 28, 0.55);
  --panel-border: rgba(255, 255, 255, 0.08);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
    Arial, sans-serif;
  color: var(--text);
  background: linear-gradient(180deg, var(--bg-top), var(--bg-bottom));
  overflow: hidden;
}

#scene {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  display: block;
  outline: none;
}

.hud {
  position: fixed;
  top: 1.25rem;
  left: 1.25rem;
  z-index: 2;
  padding: 0.75rem 1rem;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  max-width: 80vw;
}

.hud h1 {
  margin: 0;
  font-size: 1.4rem;
  letter-spacing: 0.01em;
}

.subtitle {
  margin: 0.25rem 0 0;
  color: var(--muted);
  font-size: 0.85rem;
}

.controls {
  position: fixed;
  bottom: 1.25rem;
  left: 1.25rem;
  z-index: 2;
  padding: 0.75rem 1rem;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 12px;
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  font-size: 0.9rem;
}

.control-group {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  align-items: center;
}

.control-group label {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--muted);
}

.control-group input[type="color"] {
  width: 32px;
  height: 32px;
  border: none;
  background: transparent;
  cursor: pointer;
  padding: 0;
}

.control-group .checkbox {
  cursor: pointer;
}

.hint {
  margin: 0.6rem 0 0;
  color: var(--muted);
  font-size: 0.75rem;
}

.credits {
  position: fixed;
  bottom: 0.5rem;
  right: 1rem;
  z-index: 2;
  color: var(--muted);
  font-size: 0.7rem;
}

.loading {
  position: fixed;
  inset: 0;
  z-index: 3;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(180deg, var(--bg-top), var(--bg-bottom));
  color: var(--muted);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  font-size: 0.85rem;
  transition: opacity 0.4s ease;
}

.loading.hidden {
  opacity: 0;
  pointer-events: none;
}

@media (max-width: 600px) {
  .hud h1 {
    font-size: 1.1rem;
  }
  .controls {
    right: 1.25rem;
  }
}