:root {
  --bg-primary: #121417;
  --bg-secondary: #1a1d23;
  --bg-tertiary: #22262f;
  --bg-card: #1e222b;
  --border-color: #2e3440;
  --border-light: #3b4252;
  --text-primary: #eceff4;
  --text-secondary: #d8dee9;
  --text-muted: #8892b0;
  --accent: #5e81ac;
  --accent-hover: #81a1c1;
  --accent-active: #88c0d0;
  --success: #a3be8c;
  --warning: #ebcb8b;
  --danger: #bf616a;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
  --header-height: 52px;
  --sidebar-width: 320px;
  --property-width: 340px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  font-size: 13px;
  line-height: 1.5;
}

/* Header */
.app-header {
  height: var(--header-height);
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  flex-shrink: 0;
}

.home-link {
  display: flex;
  align-items: center;
  margin-right: 12px;
}

.home-logo {
  height: 28px;
  width: auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
}

.cad-icon {
  font-size: 20px;
}

.brand-title {
  font-weight: 700;
  font-size: 16px;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.brand-subtitle {
  font-size: 12px;
  color: var(--text-muted);
  background: var(--bg-tertiary);
  padding: 2px 8px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.cad-status-tag {
  font-size: 11px;
  color: var(--success);
  background: rgba(163, 190, 140, 0.1);
  padding: 3px 10px;
  border-radius: 12px;
  border: 1px solid rgba(163, 190, 140, 0.25);
}

.header-info-button {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  padding: 5px 12px;
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 500;
  transition: all 0.15s;
}

.header-info-button:hover {
  background: var(--border-color);
  border-color: var(--border-light);
}

.info-symbol {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-size: 10px;
  font-weight: 700;
}

/* Workspace Layout */
.workspace {
  display: flex;
  flex: 1;
  height: calc(100vh - var(--header-height));
  overflow: hidden;
}

/* Left Sidebar */
.sidebar {
  width: var(--sidebar-width);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  overflow: hidden;
}

.sidebar-scroll-content {
  flex: 1;
  overflow-y: auto;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.compact-drop-zone {
  border: 2px dashed var(--border-light);
  border-radius: 8px;
  padding: 16px;
  text-align: center;
  cursor: pointer;
  background: var(--bg-card);
  transition: all 0.2s;
}

.compact-drop-zone:hover {
  border-color: var(--accent);
  background: rgba(94, 129, 172, 0.08);
}

.drop-label {
  font-weight: 600;
  font-size: 13px;
  color: var(--text-primary);
}

.drop-sublabel {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
}

.section-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.section-header h3 {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
}

.element-count-badge {
  font-size: 10px;
  background: var(--bg-tertiary);
  color: var(--accent-active);
  padding: 2px 6px;
  border-radius: 10px;
  font-weight: 600;
}

.form-select, .form-input {
  width: 100%;
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 12px;
  outline: none;
  font-family: inherit;
  transition: border-color 0.15s;
}

.form-select:focus, .form-input:focus {
  border-color: var(--accent);
}

.category-filters {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.filter-chip {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--text-secondary);
  cursor: pointer;
  user-select: none;
}

.filter-chip input {
  cursor: pointer;
}

.chip-color {
  width: 12px;
  height: 12px;
  border-radius: 3px;
  display: inline-block;
}

.tree-card {
  flex: 1;
  min-height: 250px;
  display: flex;
  flex-direction: column;
}

.tree-container {
  flex: 1;
  overflow-y: auto;
  max-height: 350px;
  font-size: 12px;
}

.tree-node {
  padding: 4px 6px;
  border-radius: 4px;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  white-space: nowrap;
  text-overflow: ellipsis;
  overflow: hidden;
}

.tree-node:hover {
  background: var(--bg-tertiary);
}

.tree-node.selected {
  background: rgba(94, 129, 172, 0.3);
  color: var(--accent-active);
  font-weight: 600;
}

.tree-empty {
  color: var(--text-muted);
  font-size: 11px;
  text-align: center;
  padding: 20px 0;
}

/* Center Viewport */
.viewport-pane {
  flex: 1;
  position: relative;
  background: #0f1115;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.viewport-container {
  flex: 1;
  position: relative;
  width: 100%;
  height: 100%;
}

#three-canvas {
  width: 100%;
  height: 100%;
  display: block;
}

.viewport-toolbar {
  position: absolute;
  top: 12px;
  left: 12px;
  display: flex;
  gap: 8px;
  z-index: 10;
}

.toolbar-group {
  background: rgba(26, 29, 35, 0.85);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 3px;
  display: flex;
  gap: 2px;
}

.toolbar-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.15s;
}

.toolbar-btn:hover {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.toolbar-btn.active {
  background: var(--accent);
  color: #fff;
}

.viewport-stats {
  position: absolute;
  bottom: 12px;
  left: 12px;
  background: rgba(26, 29, 35, 0.85);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 8px 12px;
  display: flex;
  gap: 16px;
  font-size: 11px;
  z-index: 10;
}

.stats-item {
  display: flex;
  gap: 4px;
}

.stats-label {
  color: var(--text-muted);
}

.stats-val {
  color: var(--text-primary);
  font-family: var(--font-mono);
  font-weight: 600;
}

.viewport-placeholder {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  color: var(--text-muted);
  pointer-events: none;
}

.placeholder-icon {
  font-size: 48px;
  margin-bottom: 12px;
}

.viewport-placeholder h2 {
  font-size: 18px;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.viewport-placeholder p {
  font-size: 13px;
}

.viewport-placeholder code {
  background: var(--bg-tertiary);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: var(--font-mono);
}

/* Right Property Pane */
.property-pane {
  width: var(--property-width);
  background: var(--bg-secondary);
  border-left: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  flex-shrink: 0;
  overflow: hidden;
}

.tabs-header {
  display: flex;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-primary);
}

.tab-btn {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 10px 8px;
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all 0.15s;
}

.tab-btn:hover {
  color: var(--text-primary);
}

.tab-btn.active {
  color: var(--accent-active);
  border-bottom-color: var(--accent-active);
  background: var(--bg-secondary);
  font-weight: 600;
}

.tab-content {
  display: none;
  flex: 1;
  overflow-y: auto;
  padding: 12px;
}

.tab-content.active {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.panel-section {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.panel-section h4 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
}

.prop-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 11px;
}

.prop-table td {
  padding: 5px 8px;
  border-bottom: 1px solid var(--border-color);
}

.prop-key {
  color: var(--text-muted);
  width: 40%;
}

.prop-val {
  color: var(--text-primary);
  word-break: break-all;
}

.font-mono {
  font-family: var(--font-mono);
  font-size: 10px;
}

.preview-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 8px;
  text-align: center;
}

.preview-card img {
  max-width: 100%;
  height: auto;
  border-radius: 4px;
}

.empty-state {
  color: var(--text-muted);
  font-size: 11px;
  text-align: center;
  padding: 20px 8px;
}

/* Loading Overlay */
.loading-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(15, 17, 21, 0.8);
  backdrop-filter: blur(4px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  z-index: 50;
}

.spinner {
  width: 32px;
  height: 32px;
  border: 3px solid var(--border-color);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.loading-text {
  font-size: 12px;
  font-weight: 500;
  color: var(--text-primary);
}

/* Drag Overlay */
.drag-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(18, 20, 23, 0.92);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.drag-overlay.active {
  display: flex;
}

.drag-overlay-content {
  border: 2px dashed var(--accent);
  border-radius: 16px;
  padding: 48px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.drag-overlay-icon {
  font-size: 48px;
}

.drag-overlay-text {
  font-size: 18px;
  font-weight: 600;
}

.drag-overlay-subtext {
  font-size: 12px;
  color: var(--text-muted);
}

/* Dialog */
.info-dialog {
  margin: auto;
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-light);
  border-radius: 8px;
  padding: 20px;
  width: 480px;
  max-width: 90vw;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
}

.info-dialog::backdrop {
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(2px);
}

.info-dialog-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
}

.info-dialog-title-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.info-dialog-title-row h2 {
  font-size: 16px;
  font-weight: 700;
}

.info-dialog-version {
  font-size: 11px;
  background: var(--bg-tertiary);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--accent-active);
}

.dialog-close-button {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 20px;
  cursor: pointer;
}

.dialog-close-button:hover {
  color: var(--text-primary);
}

.info-dialog-body {
  font-size: 12px;
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.info-dialog-list {
  padding-left: 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.info-dialog-footer {
  margin-top: 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 10px;
  color: var(--text-muted);
}

.btn {
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 500;
  cursor: pointer;
  border: 1px solid transparent;
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-primary);
  border-color: var(--border-color);
}

.btn-secondary:hover {
  background: var(--border-color);
}