:root {
  --bg-dark: #0f1117;
  --panel-bg: rgba(22, 27, 34, 0.88);
  --panel-border: rgba(255, 255, 255, 0.12);
  --accent-red: #e02424;
  --accent-yellow: #facc15;
  --accent-blue: #3b82f6;
  --text-main: #f3f4f6;
  --text-muted: #9ca3af;
  --card-hover: rgba(255, 255, 255, 0.06);
  --radius-lg: 16px;
  --radius-md: 10px;
  --radius-sm: 6px;
  --shadow-panel: 0 16px 36px rgba(0, 0, 0, 0.5);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

body {
  background-color: var(--bg-dark);
  color: var(--text-main);
  overflow: hidden;
  height: 100vh;
  width: 100vw;
  user-select: none;
}

/* 3D WebGL Canvas */
#webgl-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

/* Header */
.top-header {
  position: absolute;
  top: 16px;
  left: 20px;
  right: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 100;
  pointer-events: none;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  padding: 6px 14px;
  border-radius: var(--radius-lg);
  pointer-events: auto;
  box-shadow: var(--shadow-panel);
  height: 38px;
  box-sizing: border-box;
}

.brand .logo-icon {
  font-size: 1.35rem;
  line-height: 1;
}

.brand h1 {
  font-size: 1.05rem;
  font-weight: 700;
  letter-spacing: -0.3px;
  color: #fff;
  margin: 0;
  white-space: nowrap;
}

/* Collapsible Top Model Selector Dropdown */
.model-dropdown-container {
  position: relative;
  pointer-events: auto;
  z-index: 50;
}

/* Invisible hover bridge between trigger and menu */
.model-dropdown-container::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  height: 12px;
}

.model-dropdown-trigger {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  padding: 6px 14px;
  height: 38px;
  box-sizing: border-box;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-panel);
  cursor: pointer;
  color: #fff;
  font-size: 0.85rem;
  font-weight: 600;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  user-select: none;
}

.model-dropdown-trigger:hover,
.model-dropdown-container:hover .model-dropdown-trigger,
.model-dropdown-container.open .model-dropdown-trigger {
  background: rgba(15, 23, 42, 0.95);
  border-color: rgba(96, 165, 250, 0.6);
  box-shadow: 0 0 16px rgba(59, 130, 246, 0.35);
  color: #ffffff;
}

.model-dropdown-trigger .trigger-icon {
  font-size: 1rem;
}

.model-dropdown-trigger .trigger-label {
  font-weight: 600;
  max-width: 160px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  color: #e2e8f0;
}

.model-dropdown-trigger .trigger-chevron {
  font-size: 0.72rem;
  color: #94a3b8;
  margin-left: 2px;
  transition: transform 0.22s cubic-bezier(0.16, 1, 0.3, 1), color 0.2s ease;
}

.model-dropdown-container:hover .trigger-chevron,
.model-dropdown-container.open .trigger-chevron {
  transform: rotate(180deg);
  color: #60a5fa;
}

/* Dropdown Menu - Hidden by default, expands smoothly on hover / click */
.model-dropdown-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  width: 320px;
  background: rgba(15, 23, 42, 0.96);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid rgba(59, 130, 246, 0.35);
  border-radius: var(--radius-lg);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.75), 0 0 20px rgba(59, 130, 246, 0.15);
  padding: 12px;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px) scale(0.98);
  pointer-events: none;
  transition: opacity 0.2s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.2s cubic-bezier(0.16, 1, 0.3, 1),
              visibility 0.2s;
}

.model-dropdown-container:hover .model-dropdown-menu,
.model-dropdown-container.open .model-dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}

.dropdown-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 8px;
  margin-bottom: 10px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.dropdown-header-title {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  color: #94a3b8;
}

.dropdown-section-title {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  color: #60a5fa;
  margin: 10px 0 6px 2px;
}

.dropdown-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
}

.dropdown-grid .preset-btn {
  justify-content: flex-start;
  padding: 6px 10px;
  font-size: 0.76rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--radius-sm);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.dropdown-grid .preset-btn:hover {
  background: rgba(59, 130, 246, 0.18);
  border-color: rgba(59, 130, 246, 0.45);
  color: #ffffff;
  transform: translateY(-1px);
}

.dropdown-grid .preset-btn.active {
  background: rgba(37, 99, 235, 0.3);
  border-color: var(--accent-blue);
  color: #93c5fd;
  font-weight: 600;
  box-shadow: 0 0 10px rgba(59, 130, 246, 0.3);
}

.upload-preset-btn {
  width: 100%;
  box-sizing: border-box;
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.35), rgba(29, 78, 216, 0.25)) !important;
  border: 1px solid rgba(96, 165, 250, 0.55) !important;
  color: #bfdbfe !important;
  font-weight: 600;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  box-shadow: 0 0 12px rgba(59, 130, 246, 0.25);
  cursor: pointer;
  transition: all 0.18s ease;
}

.upload-preset-btn:hover {
  background: linear-gradient(135deg, rgba(37, 99, 235, 0.55), rgba(29, 78, 216, 0.45)) !important;
  border-color: #93c5fd !important;
  color: #ffffff !important;
  transform: translateY(-1px);
  box-shadow: 0 0 16px rgba(59, 130, 246, 0.5);
}

.upload-preset-btn.active {
  background: linear-gradient(135deg, #2563eb, #1d4ed8) !important;
  border-color: #60a5fa !important;
  color: #ffffff !important;
  box-shadow: 0 0 16px rgba(59, 130, 246, 0.65);
}

.dropdown-upload-row {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 8px;
}

.dropdown-upload-row .upload-preset-btn {
  flex: 1;
  margin-bottom: 0 !important;
}

.btn-advice-tip {
  background: rgba(59, 130, 246, 0.16);
  border: 1px solid rgba(59, 130, 246, 0.45);
  color: #93c5fd;
  padding: 5px 9px;
  border-radius: var(--radius-sm);
  font-size: 0.72rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: all 0.18s ease;
  white-space: nowrap;
}

.btn-advice-tip:hover,
.btn-advice-tip:active {
  background: rgba(59, 130, 246, 0.35);
  color: #ffffff;
  border-color: #60a5fa;
  transform: translateY(-1px);
}

.dropdown-tip-btn {
  padding: 8px 10px;
}

.upload-action-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-top: 6px;
}

.loaded-action-col {
  display: flex;
  flex-direction: column;
  gap: 6px;
  align-items: flex-end;
}

/* Floating Advice Bubble Tooltip */
.upload-advice-tooltip {
  position: fixed;
  z-index: 100000;
  width: 290px;
  max-width: calc(100vw - 24px);
  background: rgba(15, 23, 42, 0.96);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid rgba(59, 130, 246, 0.5);
  border-radius: var(--radius-md);
  padding: 10px 12px;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.7), 0 0 20px rgba(59, 130, 246, 0.25);
  pointer-events: none;
  opacity: 0;
  transform: translateY(6px);
  transition: opacity 0.2s cubic-bezier(0.16, 1, 0.3, 1),
              transform 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.upload-advice-tooltip.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.advice-tooltip-arrow {
  position: absolute;
  width: 10px;
  height: 10px;
  background: rgba(15, 23, 42, 0.96);
  border: 1px solid rgba(59, 130, 246, 0.5);
  transform: rotate(45deg);
}

.upload-advice-tooltip.arrow-top .advice-tooltip-arrow {
  top: -6px;
  border-bottom: none;
  border-right: none;
}

.upload-advice-tooltip.arrow-bottom .advice-tooltip-arrow {
  bottom: -6px;
  border-top: none;
  border-left: none;
}

.advice-tooltip-header {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 5px;
}

.advice-tooltip-icon {
  font-size: 0.95rem;
  line-height: 1;
}

.advice-tooltip-title {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  color: #93c5fd;
}

.advice-tooltip-content {
  font-size: 0.73rem;
  line-height: 1.45;
  color: #cbd5e1;
}

.advice-tooltip-content strong {
  color: #60a5fa;
  font-weight: 600;
}

.advice-tooltip-content code {
  background: rgba(255, 255, 255, 0.1);
  padding: 1px 4px;
  border-radius: 3px;
  font-size: 0.68rem;
  font-family: monospace;
  color: #fbbf24;
}

.preset-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-main);
  padding: 6px 10px;
  border-radius: var(--radius-md);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}

.preset-btn:hover {
  background: var(--card-hover);
  border-color: var(--panel-border);
  transform: translateY(-1px);
}

.preset-btn.active {
  background: rgba(59, 130, 246, 0.2);
  border-color: var(--accent-blue);
  color: #60a5fa;
}

/* Floating UI Panels */
.panel {
  position: absolute;
  z-index: 10;
  background: var(--panel-bg);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-panel);
  padding: 16px;
  max-height: calc(100vh - 84px);
  overflow-y: auto;
  pointer-events: auto;
  transition: opacity 0.2s ease;
}

.panel::-webkit-scrollbar {
  width: 5px;
}

.panel::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.2);
  border-radius: 4px;
}

/* Left Panel - Controls */
.left-panel {
  top: 64px;
  left: 20px;
  width: 320px;
}

/* Right Panel - Stats & Export */
.right-panel {
  top: 64px;
  right: 20px;
  width: 290px;
}

/* Panel Sections */
.panel-section {
  margin-bottom: 18px;
}

.panel-section:last-child {
  margin-bottom: 0;
}

.section-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text-muted);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Redesigned File Upload Zone */
.upload-card {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: 1.5px dashed rgba(255, 255, 255, 0.25);
  border-radius: var(--radius-md);
  padding: 18px 12px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s ease;
  background: rgba(0, 0, 0, 0.2);
}

.upload-card:hover, .upload-card.dragover {
  border-color: var(--accent-blue);
  background: rgba(59, 130, 246, 0.12);
}

.upload-icon {
  font-size: 1.8rem;
  margin-bottom: 6px;
}

.upload-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: #fff;
}

.upload-subtitle {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: 3px;
  margin-bottom: 10px;
}

.btn-browse {
  font-size: 0.75rem;
  font-weight: 600;
  background: rgba(59, 130, 246, 0.25);
  border: 1px solid #3b82f6;
  color: #93c5fd;
  padding: 5px 12px;
  border-radius: 6px;
  transition: all 0.15s ease;
}

.upload-card:hover .btn-browse {
  background: #2563eb;
  color: #fff;
}

.file-input {
  display: none;
}

/* Loaded File Card */
.loaded-card {
  display: none;
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-md);
  padding: 10px;
  gap: 10px;
}

.thumb-wrapper {
  position: relative;
  width: 52px;
  height: 52px;
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--panel-border);
  background-color: #1e293b;
  background-image: 
    linear-gradient(45deg, #334155 25%, transparent 25%), 
    linear-gradient(-45deg, #334155 25%, transparent 25%), 
    linear-gradient(45deg, transparent 75%, #334155 75%), 
    linear-gradient(-45deg, transparent 75%, #334155 75%);
  background-size: 8px 8px;
  background-position: 0 0, 0 4px, 4px -4px, -4px 0px;
  flex-shrink: 0;
}

.thumb-img {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.loaded-meta {
  flex: 1;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.loaded-name {
  font-size: 0.8rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: #fff;
}

.loaded-size {
  font-size: 0.68rem;
  color: var(--text-muted);
  margin-top: 2px;
}

.loaded-badge {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 600;
  color: #34d399;
  margin-top: 3px;
}

.loaded-badge.badge-ball {
  color: #fb923c;
  font-weight: 700;
  text-shadow: 0 0 10px rgba(251, 146, 60, 0.4);
}

.btn-change-file {
  background: transparent;
  border: 1px solid var(--panel-border);
  color: var(--text-main);
  font-size: 0.72rem;
  font-weight: 500;
  padding: 4px 8px;
  border-radius: 5px;
  cursor: pointer;
  align-self: center;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.btn-change-file:hover {
  background: var(--card-hover);
  border-color: #60a5fa;
  color: #60a5fa;
}

/* Model Orientation Rotation Controls */
.model-orientation-group {
  margin-top: 10px;
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-md);
  padding: 8px 10px;
}

.orientation-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  margin-bottom: 6px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.rot-status-badge {
  font-family: monospace;
  font-size: 0.68rem;
  color: #38bdf8;
  background: rgba(56, 189, 248, 0.12);
  padding: 1px 6px;
  border-radius: 4px;
}

.rotation-btn-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr) 34px;
  gap: 5px;
}

.btn-rotate-axis {
  background: #1e293b;
  border: 1px solid #334155;
  color: #f1f5f9;
  border-radius: 6px;
  padding: 6px 4px;
  font-size: 0.72rem;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 3px;
  transition: all 0.15s ease;
  user-select: none;
}

.btn-rotate-axis:hover {
  background: #334155;
  border-color: #3b82f6;
  color: #60a5fa;
  transform: translateY(-1px);
}

.btn-rotate-axis:active {
  transform: translateY(0);
  background: #2563eb;
  color: #fff;
}

.btn-rot-reset {
  background: #0f172a;
  color: #94a3b8;
  padding: 6px 0;
  font-size: 0.85rem;
}

.btn-rot-reset:hover {
  background: #1e1b4b;
  color: #f87171;
  border-color: #ef4444;
}

/* Slider Controls */
.control-group {
  margin-bottom: 12px;
}

.control-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.78rem;
  font-weight: 500;
  margin-bottom: 6px;
}

.control-val {
  font-family: monospace;
  font-size: 0.8rem;
  color: #60a5fa;
}

input[type="range"] {
  width: 100%;
  height: 5px;
  background: rgba(255, 255, 255, 0.15);
  border-radius: 3px;
  outline: none;
  -webkit-appearance: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  background: #3b82f6;
  border: 2px solid #fff;
  cursor: pointer;
  transition: transform 0.1s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

/* Select & Radio Groups */
.select-input {
  width: 100%;
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid var(--panel-border);
  color: #fff;
  padding: 7px 10px;
  border-radius: var(--radius-sm);
  font-size: 0.8rem;
  outline: none;
  cursor: pointer;
}

.toggle-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 0;
  font-size: 0.8rem;
}

/* Modern Toggle Switch */
.switch {
  position: relative;
  display: inline-block;
  width: 36px;
  height: 20px;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider-round {
  position: absolute;
  cursor: pointer;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: rgba(255, 255, 255, 0.2);
  transition: .2s;
  border-radius: 20px;
}

.slider-round:before {
  position: absolute;
  content: "";
  height: 14px;
  width: 14px;
  left: 3px;
  bottom: 3px;
  background-color: white;
  transition: .2s;
  border-radius: 50%;
}

input:checked + .slider-round {
  background-color: #3b82f6;
}

input:checked + .slider-round:before {
  transform: translateX(16px);
}

/* Statistics Grid */
.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-bottom: 12px;
}

.stat-card {
  background: rgba(0, 0, 0, 0.25);
  padding: 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--panel-border);
  text-align: center;
}

.stat-value {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--accent-yellow);
  font-family: monospace;
}

.stat-label {
  font-size: 0.68rem;
  color: var(--text-muted);
  text-transform: uppercase;
  margin-top: 2px;
}

/* Color Breakdown Swatches */
.palette-list {
  max-height: 140px;
  overflow-y: auto;
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-sm);
  background: rgba(0, 0, 0, 0.2);
  padding: 4px;
}

.palette-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 4px 6px;
  font-size: 0.72rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
}

.palette-item:last-child {
  border-bottom: none;
}

.color-dot {
  width: 12px;
  height: 12px;
  border-radius: 3px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  flex-shrink: 0;
}

.color-name {
  flex: 1;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.color-count {
  font-family: monospace;
  font-weight: 600;
  color: #fff;
}

/* Action Buttons */
.btn-primary {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  color: #fff;
  border: none;
  padding: 10px 14px;
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
  margin-bottom: 8px;
}

.btn-primary:hover {
  filter: brightness(1.1);
  transform: translateY(-1px);
}

.btn-secondary {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: rgba(255, 255, 255, 0.07);
  color: #fff;
  border: 1px solid var(--panel-border);
  padding: 8px 12px;
  border-radius: var(--radius-md);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.12);
}

/* Viewport Bottom Toolbar */
.bottom-toolbar {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 8px;
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--panel-border);
  padding: 6px 12px;
  border-radius: var(--radius-lg);
  z-index: 10;
  box-shadow: var(--shadow-panel);
}

.tool-btn {
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-main);
  padding: 6px 10px;
  border-radius: var(--radius-md);
  font-size: 0.78rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: all 0.15s ease;
}

.tool-btn:hover {
  background: var(--card-hover);
  border-color: var(--panel-border);
}

.tool-btn.active {
  background: rgba(59, 130, 246, 0.25);
  border-color: var(--accent-blue);
  color: #60a5fa;
}

/* Loading Overlay */
.loading-overlay {
  position: absolute;
  top: 0; left: 0; width: 100%; height: 100%;
  background: rgba(15, 17, 23, 0.7);
  backdrop-filter: blur(4px);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 12px;
  z-index: 100;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}

.loading-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.spinner {
  width: 38px;
  height: 38px;
  border: 3px solid rgba(255, 255, 255, 0.1);
  border-top-color: var(--accent-yellow);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.loading-text {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-main);
}

/* Color Swatch Grid */
.color-swatch-grid {
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  gap: 6px;
  margin-top: 8px;
}

.swatch-btn {
  width: 28px;
  height: 28px;
  border-radius: 6px;
  border: 2px solid rgba(255, 255, 255, 0.15);
  cursor: pointer;
  transition: all 0.15s ease;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
  position: relative;
}

.swatch-btn:hover {
  transform: scale(1.15);
  border-color: rgba(255, 255, 255, 0.6);
  box-shadow: 0 0 8px rgba(255, 255, 255, 0.4);
}

.swatch-btn.active {
  border-color: #ffffff;
  transform: scale(1.12);
  box-shadow: 0 0 10px rgba(59, 130, 246, 0.9), 0 0 0 2px rgba(59, 130, 246, 0.6);
}

.swatch-custom-label {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 6px;
  border: 1px solid var(--panel-border);
  background: var(--card-bg);
  cursor: pointer;
  font-size: 0.85rem;
  position: relative;
  overflow: hidden;
  transition: all 0.15s ease;
}

.swatch-custom-label:hover {
  background: var(--card-hover);
  transform: scale(1.1);
  border-color: #60a5fa;
}

.custom-color-input {
  position: absolute;
  opacity: 0;
  width: 100%;
  height: 100%;
  cursor: pointer;
}

/* Interactive Palette Item */
.palette-item.clickable {
  cursor: pointer;
  transition: all 0.15s ease;
  padding: 4px 6px;
  border-radius: 6px;
}

.palette-item.clickable:hover {
  background: rgba(255, 255, 255, 0.08);
  transform: translateX(2px);
}

/* Resolution Auto-Hollow Badge */
.res-badge {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  background: rgba(16, 185, 129, 0.2);
  color: #34d399;
  border: 1px solid rgba(16, 185, 129, 0.35);
  font-size: 0.68rem;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: 10px;
  margin-left: 6px;
  vertical-align: middle;
}

/* Element Breakdown Badges */
.element-breakdown-card {
  background: rgba(0, 0, 0, 0.25);
  padding: 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--panel-border);
  margin-bottom: 12px;
}

.element-tags {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-top: 6px;
}

.element-tag {
  display: flex;
  align-items: center;
  gap: 4px;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 6px;
  padding: 4px 6px;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.element-tag span {
  font-weight: 700;
  color: #fff;
  font-family: monospace;
}

.element-tag:last-child:nth-child(odd) {
  grid-column: span 2;
  justify-content: center;
}

#tag-tyres {
  background: rgba(254, 196, 0, 0.08);
  border-color: rgba(254, 196, 0, 0.25);
  color: #fec400;
}

/* LEGO Tyres & Wheels Section Styling */
.btn-pick-wheel {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.15), rgba(37, 99, 235, 0.25));
  border: 1px solid rgba(96, 165, 250, 0.4);
  color: #93c5fd;
  font-weight: 600;
  font-size: 0.8rem;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-pick-wheel:hover {
  background: linear-gradient(135deg, rgba(59, 130, 246, 0.3), rgba(37, 99, 235, 0.4));
  border-color: #93c5fd;
  color: #fff;
  transform: translateY(-1px);
}

.btn-pick-wheel.active {
  background: linear-gradient(135deg, rgba(234, 179, 8, 0.25), rgba(202, 138, 4, 0.35));
  border-color: #facc15;
  color: #fef08a;
  box-shadow: 0 0 14px rgba(250, 204, 21, 0.35);
  animation: pulse-border 1.5s infinite;
}

@keyframes pulse-border {
  0%, 100% { border-color: #facc15; box-shadow: 0 0 8px rgba(250, 204, 21, 0.25); }
  50% { border-color: #ca8a04; box-shadow: 0 0 16px rgba(250, 204, 21, 0.55); }
}

.pick-hint {
  font-size: 0.72rem;
  color: #fde047;
  background: rgba(250, 204, 21, 0.1);
  border: 1px dashed rgba(250, 204, 21, 0.3);
  padding: 6px 8px;
  border-radius: 6px;
  margin-top: 6px;
  line-height: 1.35;
  text-align: center;
}

.rim-swatches {
  display: flex;
  gap: 8px;
  align-items: center;
  margin-top: 6px;
}

.rim-swatch {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.2);
  cursor: pointer;
  transition: all 0.15s ease;
  position: relative;
  outline: none;
}

.rim-swatch:hover {
  transform: scale(1.15);
  border-color: #fff;
}

.rim-swatch.active {
  border-color: #fff;
  box-shadow: 0 0 0 2px var(--bg-dark), 0 0 10px rgba(255, 255, 255, 0.6);
  transform: scale(1.12);
}

.control-details {
  background: rgba(0, 0, 0, 0.2);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-sm);
  padding: 8px 10px;
  margin-top: 10px;
}

.control-details summary {
  font-size: 0.76rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  outline: none;
  user-select: none;
  transition: color 0.15s ease;
}

.control-details summary:hover {
  color: #fff;
}

.control-details[open] summary {
  margin-bottom: 8px;
  color: #93c5fd;
}

.control-details .details-content {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

#webgl-canvas.picking-wheel {
  cursor: crosshair !important;
}

#webgl-canvas {
  touch-action: none;
}

/* Mobile Advisory Notice Banner */
.mobile-notice {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10000;
  background: linear-gradient(90deg, #1e3a8a, #2563eb, #1e3a8a);
  color: #eff6ff;
  display: none;
  align-items: center;
  justify-content: space-between;
  padding: 6px 14px;
  font-size: 0.74rem;
  font-weight: 500;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.4);
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.mobile-notice-content {
  display: flex;
  align-items: center;
  gap: 8px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.mobile-notice-icon {
  font-size: 0.95rem;
}

.btn-dismiss-notice {
  background: rgba(255, 255, 255, 0.15);
  border: none;
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-left: 8px;
  transition: background 0.15s ease;
}

.btn-dismiss-notice:hover {
  background: rgba(255, 255, 255, 0.3);
}

.mobile-notice.dismissed {
  transform: translateY(-100%);
  opacity: 0;
  pointer-events: none;
}

/* Mobile Panel Header */
.mobile-panel-header {
  display: none;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 10px;
  margin-bottom: 12px;
  border-bottom: 1px solid var(--panel-border);
  font-size: 0.85rem;
  font-weight: 700;
  color: #fff;
}

.btn-close-panel {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid var(--panel-border);
  color: #f1f5f9;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.15s ease;
}

.btn-close-panel:hover {
  background: rgba(239, 68, 68, 0.3);
  border-color: #ef4444;
}

/* Mobile Drawer Backdrop */
.mobile-backdrop {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
  z-index: 20;
  opacity: 0;
  transition: opacity 0.25s ease;
  pointer-events: none;
}

.mobile-backdrop.active {
  opacity: 1;
  pointer-events: auto;
}

/* Floating Mobile Navigation Dock */
.mobile-nav-bar {
  display: none;
  position: fixed;
  bottom: 14px;
  left: 12px;
  right: 12px;
  z-index: 35;
  background: rgba(15, 23, 42, 0.95);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 26px;
  padding: 6px 8px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.65);
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.mobile-nav-bar.panel-open {
  grid-template-columns: 1fr 1fr 1fr;
}

.mobile-nav-btn {
  background: #1e293b;
  border: 1px solid var(--panel-border);
  color: #f1f5f9;
  padding: 8px 12px;
  border-radius: 20px;
  font-size: 0.78rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  cursor: pointer;
  transition: all 0.15s ease;
  user-select: none;
}

.mobile-nav-btn:hover,
.mobile-nav-btn.active {
  background: #2563eb;
  border-color: #3b82f6;
  color: #fff;
  box-shadow: 0 2px 10px rgba(37, 99, 235, 0.4);
}

/* ==========================================================
   Responsive Media Queries (Mobile & Tablets <= 840px)
   ========================================================== */
@media (max-width: 840px) {
  /* Show Mobile Notice & Nav */
  .mobile-notice:not(.dismissed) {
    display: flex;
  }

  .mobile-nav-bar {
    display: grid;
  }

  .mobile-panel-header {
    display: flex;
  }

  .mobile-backdrop {
    display: block;
  }

  /* Header adjustments */
  .top-header {
    top: 34px;
    left: 8px;
    right: 8px;
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    pointer-events: none;
  }

  .mobile-notice.dismissed ~ .top-header {
    top: 10px;
  }

  .brand {
    padding: 6px 10px;
    height: 34px;
    border-radius: var(--radius-md);
    flex-shrink: 0;
  }

  .brand h1 {
    font-size: 0.88rem;
  }

  .brand .logo-icon {
    font-size: 1.15rem;
  }

  .model-dropdown-container {
    flex-shrink: 0;
  }

  .model-dropdown-trigger {
    padding: 5px 10px;
    height: 34px;
    font-size: 0.78rem;
    gap: 6px;
    border-radius: var(--radius-md);
  }

  .model-dropdown-trigger .trigger-label {
    max-width: 105px;
  }

  .model-dropdown-menu {
    position: absolute;
    top: calc(100% + 6px);
    right: 0;
    left: auto;
    width: min(340px, calc(100vw - 16px));
    max-width: none;
    max-height: calc(100vh - 130px);
    overflow-y: auto;
  }

  /* Panels as Bottom Sheet Drawers on Mobile */
  .panel {
    position: fixed;
    top: auto;
    bottom: calc(max(14px, env(safe-area-inset-bottom, 14px)) + 54px);
    left: 8px;
    right: 8px;
    width: auto;
    max-height: 65vh;
    border-radius: 16px 16px var(--radius-md) var(--radius-md);
    transform: translateY(120%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.25s ease;
    z-index: 25;
    box-shadow: 0 -10px 40px rgba(0, 0, 0, 0.75);
  }

  .panel.mobile-open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .left-panel, .right-panel {
    left: 8px;
    right: 8px;
    width: auto;
  }

  /* Viewport Bottom Toolbar */
  .bottom-toolbar {
    bottom: calc(max(14px, env(safe-area-inset-bottom, 14px)) + 54px);
    max-width: calc(100vw - 16px);
    overflow-x: auto;
    scrollbar-width: none;
    -webkit-overflow-scrolling: touch;
    flex-wrap: nowrap;
    padding: 4px 8px;
    gap: 6px;
    z-index: 15;
  }

  .bottom-toolbar::-webkit-scrollbar {
    display: none;
  }

  .tool-btn {
    padding: 5px 8px;
    font-size: 0.72rem;
    white-space: nowrap;
    flex-shrink: 0;
  }
}

@media (min-width: 841px) {
  .mobile-notice {
    display: none !important;
  }
  .mobile-nav-bar {
    display: none !important;
  }
}

/* ==========================================================
   TUTORIAL / GUIDANCE STEP-BY-STEP TOUR SYSTEM
   ========================================================== */
.btn-tour-trigger {
  background: rgba(59, 130, 246, 0.16);
  border: 1px solid rgba(59, 130, 246, 0.45);
  color: #93c5fd;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 3px 9px;
  border-radius: 20px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 4px;
  transition: all 0.18s ease;
  margin-left: 8px;
  white-space: nowrap;
}

.btn-tour-trigger:hover {
  background: rgba(59, 130, 246, 0.35);
  color: #ffffff;
  border-color: #60a5fa;
  transform: translateY(-1px);
}

.tutorial-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: 99990;
  pointer-events: auto;
}

.tutorial-spotlight {
  position: fixed;
  border-radius: 12px;
  box-shadow: 0 0 0 9999px rgba(10, 15, 30, 0.78), 0 0 24px rgba(59, 130, 246, 0.85);
  border: 2px solid #3b82f6;
  pointer-events: none;
  transition: top 0.3s cubic-bezier(0.25, 1, 0.5, 1),
              left 0.3s cubic-bezier(0.25, 1, 0.5, 1),
              width 0.3s cubic-bezier(0.25, 1, 0.5, 1),
              height 0.3s cubic-bezier(0.25, 1, 0.5, 1),
              opacity 0.2s ease;
  z-index: 99992;
  animation: spotlightPulse 2s infinite ease-in-out;
}

@keyframes spotlightPulse {
  0%, 100% {
    box-shadow: 0 0 0 9999px rgba(10, 15, 30, 0.78), 0 0 16px rgba(59, 130, 246, 0.7);
    border-color: #3b82f6;
  }
  50% {
    box-shadow: 0 0 0 9999px rgba(10, 15, 30, 0.78), 0 0 30px rgba(96, 165, 250, 0.95);
    border-color: #60a5fa;
  }
}

.tutorial-bubble {
  position: fixed;
  z-index: 99995;
  width: 330px;
  max-width: calc(100vw - 28px);
  background: rgba(17, 24, 39, 0.97);
  border: 1px solid rgba(59, 130, 246, 0.45);
  border-radius: 16px;
  padding: 16px 18px;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.85), 0 0 25px rgba(37, 99, 235, 0.35);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  color: #f1f5f9;
  transition: top 0.3s cubic-bezier(0.25, 1, 0.5, 1),
              left 0.3s cubic-bezier(0.25, 1, 0.5, 1),
              transform 0.2s ease,
              opacity 0.2s ease;
  animation: bubblePop 0.28s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes bubblePop {
  0% {
    opacity: 0;
    transform: scale(0.92) translateY(6px);
  }
  100% {
    opacity: 1;
    transform: scale(1) translateY(0);
  }
}

.tutorial-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.tutorial-badge {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  color: #ffffff;
  padding: 3px 8px;
  border-radius: 12px;
}

.tutorial-btn-close {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 0.95rem;
  cursor: pointer;
  padding: 2px 6px;
  border-radius: 6px;
  transition: all 0.15s ease;
}

.tutorial-btn-close:hover {
  background: rgba(239, 68, 68, 0.2);
  color: #ef4444;
}

.tutorial-title {
  font-size: 0.98rem;
  font-weight: 700;
  margin: 0 0 8px 0;
  color: #ffffff;
  display: flex;
  align-items: center;
  gap: 6px;
}

.tutorial-body {
  font-size: 0.82rem;
  line-height: 1.45;
  color: #cbd5e1;
  margin-bottom: 14px;
}

.tutorial-body strong {
  color: #60a5fa;
  font-weight: 600;
}

.tutorial-body code {
  background: rgba(255, 255, 255, 0.1);
  padding: 1px 4px;
  border-radius: 4px;
  font-size: 0.76rem;
  font-family: monospace;
  color: #fbbf24;
}

.tutorial-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: 12px;
}

.tutorial-dots {
  display: flex;
  align-items: center;
  gap: 5px;
}

.tutorial-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.2);
  transition: all 0.2s ease;
}

.tutorial-dot.active {
  width: 16px;
  border-radius: 4px;
  background: #3b82f6;
  box-shadow: 0 0 8px rgba(59, 130, 246, 0.7);
}

.tutorial-actions {
  display: flex;
  align-items: center;
  gap: 6px;
}

.tutorial-btn {
  font-size: 0.76rem;
  font-weight: 600;
  padding: 6px 12px;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.tutorial-btn-secondary {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: #cbd5e1;
}

.tutorial-btn-secondary:hover {
  background: rgba(255, 255, 255, 0.15);
  color: #ffffff;
}

.tutorial-btn-primary {
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  border: 1px solid #3b82f6;
  color: #ffffff;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.4);
}

.tutorial-btn-primary:hover {
  filter: brightness(1.1);
  transform: translateY(-1px);
}

@media (max-width: 840px) {
  .tutorial-bubble {
    width: calc(100vw - 24px) !important;
    left: 12px !important;
    right: 12px !important;
    transform: none !important;
    padding: 14px 16px;
  }
}