:root {
  --panel-bg: rgba(16, 20, 26, 0.78);
  --panel-border: rgba(255, 255, 255, 0.09);
  --text: #e8eef2;
  --text-dim: #9fb0bc;
  --accent: #e8a95e;
  --accent-dim: rgba(232, 169, 94, 0.16);
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  overflow: hidden;
  background: #0b0e13;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  color: var(--text);
}

#scene {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

/* ---------- Brand ---------- */

#brand {
  position: fixed;
  top: 22px;
  left: 26px;
  pointer-events: none;
  user-select: none;
  z-index: 5;
}

#brand h1 {
  margin: 0;
  font-size: 22px;
  font-weight: 650;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  text-shadow: 0 2px 12px rgba(0, 0, 0, 0.45);
}

#brand p {
  margin: 4px 0 0;
  font-size: 12px;
  color: var(--text-dim);
  letter-spacing: 0.04em;
  text-shadow: 0 1px 8px rgba(0, 0, 0, 0.5);
}

/* ---------- Control panel ---------- */

#panel {
  position: fixed;
  top: 18px;
  right: 18px;
  width: 264px;
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: 14px;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: 0 10px 34px rgba(0, 0, 0, 0.35);
  z-index: 10;
  overflow: hidden;
}

#panel-toggle {
  display: none;
  width: 100%;
  padding: 10px 14px;
  background: transparent;
  border: none;
  color: var(--text);
  font-size: 16px;
  text-align: right;
  cursor: pointer;
}

#panel-body { padding: 16px 16px 14px; }

.group { margin-bottom: 15px; }
.group:last-child { margin-bottom: 2px; }

.group > label {
  display: flex;
  justify-content: space-between;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 7px;
}

.value { color: var(--accent); font-variant-numeric: tabular-nums; }

.btn-row { display: flex; gap: 6px; }
.btn-row.wrap { flex-wrap: wrap; }

.btn-row button {
  flex: 1;
  padding: 6px 4px;
  font-size: 12px;
  font-family: inherit;
  color: var(--text-dim);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid transparent;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.btn-row button:hover { color: var(--text); background: rgba(255, 255, 255, 0.1); }

.btn-row button.active {
  color: var(--accent);
  background: var(--accent-dim);
  border-color: rgba(232, 169, 94, 0.45);
}

.btn-row.wrap button { flex: 0 0 auto; padding: 5px 10px; }

input[type="range"] {
  width: 100%;
  height: 20px;
  appearance: none;
  -webkit-appearance: none;
  background: transparent;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-runnable-track {
  height: 4px;
  border-radius: 2px;
  background: rgba(255, 255, 255, 0.14);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px;
  height: 14px;
  margin-top: -5px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #14181f;
}

input[type="range"]::-moz-range-track {
  height: 4px;
  border-radius: 2px;
  background: rgba(255, 255, 255, 0.14);
}

input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid #14181f;
}

.chk-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 7px;
}

.chk-row input[type="checkbox"] {
  width: 14px;
  height: 14px;
  accent-color: var(--accent);
  cursor: pointer;
}

.chk-row label {
  font-size: 12.5px;
  color: var(--text);
  cursor: pointer;
  text-transform: none;
  letter-spacing: normal;
  font-weight: 400;
}

/* ---------- Hint / loader / error ---------- */

#hint {
  position: fixed;
  bottom: 16px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: rgba(232, 238, 242, 0.55);
  text-shadow: 0 1px 6px rgba(0, 0, 0, 0.5);
  pointer-events: none;
  user-select: none;
  z-index: 5;
}

#loader {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 14px;
  background: #0b0e13;
  z-index: 50;
  transition: opacity 0.6s ease;
}

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

#loader p { color: var(--text-dim); font-size: 13px; letter-spacing: 0.05em; }

.spinner {
  width: 34px;
  height: 34px;
  border: 3px solid rgba(255, 255, 255, 0.12);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.9s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

#webgl-error {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #0b0e13;
  z-index: 60;
  color: var(--text-dim);
}

/* ---------- Small screens ---------- */

@media (max-width: 560px) {
  #panel-toggle { display: block; }
  #panel-body { display: none; }
  #panel.open #panel-body { display: block; }
  #panel { width: min(264px, calc(100vw - 24px)); }
  #brand h1 { font-size: 17px; }
  #hint { display: none; }
}