/* ─── Reset & base ──────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0a0a0f;
  --panel-bg:  rgba(10, 12, 20, 0.88);
  --border:    rgba(100, 120, 180, 0.25);
  --accent:    #4a9eff;
  --accent2:   #7ec8c8;
  --text:      #d4dde8;
  --text-dim:  #6a7a8a;
  --panel-w:   280px;
  --radius:    8px;
  --font:      'Inter', 'Segoe UI', system-ui, sans-serif;
}

html, body {
  width: 100%; height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 13px;
  overflow: hidden;
  user-select: none;
}

/* ─── Canvas ────────────────────────────────────────────────── */
#canvas-container {
  position: fixed;
  inset: 0;
}
#canvas-container canvas {
  display: block;
  width: 100% !important;
  height: 100% !important;
}

/* ─── Loading overlay ───────────────────────────────────────── */
#loading-overlay {
  position: fixed;
  inset: 0;
  background: var(--bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 200;
  transition: opacity 0.6s ease;
}
#loading-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}
.spinner {
  width: 52px; height: 52px;
  border: 3px solid rgba(74,158,255,0.2);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.9s linear infinite;
  margin-bottom: 20px;
}
@keyframes spin { to { transform: rotate(360deg); } }
.loading-label {
  font-size: 14px;
  color: var(--text-dim);
  letter-spacing: 0.05em;
}
.loading-sub {
  font-size: 11px;
  color: #3a4a5a;
  margin-top: 6px;
}

/* ─── Error overlay ─────────────────────────────────────────── */
#error-overlay {
  position: fixed;
  inset: 0;
  background: var(--bg);
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 200;
  padding: 32px;
  text-align: center;
}
#error-overlay.visible { display: flex; }
.error-icon { font-size: 48px; margin-bottom: 16px; opacity: 0.7; }
.error-title { font-size: 18px; color: #e87070; margin-bottom: 8px; font-weight: 600; }
.error-body  { font-size: 13px; color: var(--text-dim); max-width: 420px; line-height: 1.6; }

/* ─── Control panel ─────────────────────────────────────────── */
#panel {
  position: fixed;
  top: 16px;
  right: 16px;
  width: var(--panel-w);
  background: var(--panel-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
  z-index: 100;
  backdrop-filter: blur(12px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.5);
}

.panel-title {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent2);
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.control-group {
  margin-bottom: 14px;
}
.control-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 11px;
  color: var(--text-dim);
  margin-bottom: 5px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.control-value {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

/* Sliders */
input[type=range] {
  -webkit-appearance: none;
  width: 100%; height: 4px;
  border-radius: 2px;
  background: rgba(74,158,255,0.18);
  outline: none;
  cursor: pointer;
}
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 6px rgba(74,158,255,0.5);
  cursor: pointer;
  transition: transform 0.1s;
}
input[type=range]::-webkit-slider-thumb:hover { transform: scale(1.2); }

/* Axis toggle */
.axis-toggle {
  display: flex;
  gap: 6px;
}
.axis-btn {
  flex: 1;
  padding: 5px 0;
  border: 1px solid var(--border);
  border-radius: 5px;
  background: transparent;
  color: var(--text-dim);
  font-size: 11px;
  font-family: var(--font);
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: all 0.15s;
  text-transform: uppercase;
}
.axis-btn:hover { border-color: var(--accent); color: var(--accent); }
.axis-btn.active {
  background: rgba(74,158,255,0.18);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 600;
}

/* Toggle switch */
.toggle-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
  font-size: 11px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.toggle-switch {
  position: relative;
  width: 34px; height: 18px;
}
.toggle-switch input { opacity: 0; width: 0; height: 0; }
.toggle-track {
  position: absolute;
  inset: 0;
  border-radius: 9px;
  background: rgba(255,255,255,0.08);
  border: 1px solid var(--border);
  cursor: pointer;
  transition: background 0.2s;
}
.toggle-track::after {
  content: '';
  position: absolute;
  top: 2px; left: 2px;
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--text-dim);
  transition: transform 0.2s, background 0.2s;
}
.toggle-switch input:checked + .toggle-track {
  background: rgba(74,158,255,0.3);
  border-color: var(--accent);
}
.toggle-switch input:checked + .toggle-track::after {
  transform: translateX(16px);
  background: var(--accent);
}

/* Buttons */
.btn-row {
  display: flex;
  gap: 8px;
  margin-top: 4px;
}
.btn {
  flex: 1;
  padding: 7px 0;
  border: 1px solid var(--border);
  border-radius: 5px;
  background: transparent;
  color: var(--text-dim);
  font-size: 11px;
  font-family: var(--font);
  letter-spacing: 0.05em;
  cursor: pointer;
  transition: all 0.15s;
  text-transform: uppercase;
}
.btn:hover {
  background: rgba(74,158,255,0.12);
  border-color: var(--accent);
  color: var(--text);
}
.btn:active { transform: scale(0.97); }

/* Divider */
.divider {
  height: 1px;
  background: var(--border);
  margin: 12px 0;
}

/* Info strip */
#info-strip {
  position: fixed;
  bottom: 12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--panel-bg);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 5px 16px;
  font-size: 11px;
  color: var(--text-dim);
  backdrop-filter: blur(10px);
  white-space: nowrap;
  z-index: 100;
}