:root {
  --bg-primary: #F5F5F7;
  --bg-secondary: #FFFFFF;
  --bg-toolbar: #FFFFFF;
  --border-color: #E0E0E0;
  --text-primary: #1D1D1F;
  --text-secondary: #86868B;
  --accent: #007AFF;
  --accent-hover: #0056CC;
  --accent-light: rgba(0, 122, 255, 0.1);
  --danger: #FF3B30;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 4px 12px rgba(0, 0, 0, 0.12);
  --radius: 8px;
  --radius-sm: 6px;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --palette-width: 200px;
  --properties-width: 280px;
  --toolbar-height: 48px;
}

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

html, body {
  height: 100%;
  overflow: hidden;
  font-family: var(--font);
  font-size: 14px;
  color: var(--text-primary);
  background: var(--bg-primary);
}

#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

/* Toolbar */
.toolbar {
  display: flex;
  align-items: center;
  height: var(--toolbar-height);
  background: var(--bg-toolbar);
  border-bottom: 1px solid var(--border-color);
  padding: 0 16px;
  gap: 8px;
  z-index: 100;
  flex-shrink: 0;
}

.toolbar-title {
  font-weight: 700;
  font-size: 16px;
  color: var(--text-primary);
  letter-spacing: -0.3px;
}

.toolbar-group {
  display: flex;
  align-items: center;
  gap: 4px;
}

.toolbar-group:not(:last-child) {
  padding-right: 12px;
  border-right: 1px solid var(--border-color);
}

.toolbar-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--text-primary);
  font-size: 13px;
  font-family: var(--font);
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
}

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

.toolbar-btn.active {
  background: var(--accent-light);
  color: var(--accent);
  border-color: var(--accent);
}

.toolbar-btn:active {
  transform: scale(0.97);
}

.toolbar-spacer {
  flex: 1;
}

.status-text {
  font-size: 12px;
  color: var(--text-secondary);
}

/* Main content area */
#viewport {
  flex: 1;
  display: flex;
  position: relative;
  overflow: hidden;
  background: var(--bg-primary);
}

#canvas3d {
  flex: 1;
  display: block;
  width: 100%;
  height: 100%;
}

/* Palette */
.palette {
  width: var(--palette-width);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  padding: 16px 12px;
  overflow-y: auto;
  flex-shrink: 0;
}

.palette-title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.palette-section {
  margin-bottom: 16px;
}

.palette-section-label {
  display: block;
  font-size: 11px;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

.palette-items {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.palette-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  cursor: grab;
  font-size: 13px;
  color: var(--text-primary);
  transition: background 0.15s ease;
  user-select: none;
}

.palette-item:hover {
  background: var(--bg-primary);
}

.palette-item:active {
  cursor: grabbing;
}

.palette-icon {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
}

/* Properties Panel */
.properties {
  width: var(--properties-width);
  background: var(--bg-secondary);
  border-left: 1px solid var(--border-color);
  padding: 16px 12px;
  overflow-y: auto;
  flex-shrink: 0;
}

.properties-title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.properties-empty {
  color: var(--text-secondary);
  font-size: 13px;
  text-align: center;
  padding: 24px 0;
}

.prop-group {
  margin-bottom: 16px;
}

.prop-group-label {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-secondary);
  margin-bottom: 8px;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--border-color);
}

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

.prop-label {
  font-size: 12px;
  color: var(--text-secondary);
  min-width: 50px;
}

.prop-input {
  flex: 1;
  padding: 5px 8px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-family: var(--font);
  color: var(--text-primary);
  background: var(--bg-primary);
  transition: border-color 0.15s ease;
}

.prop-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 2px var(--accent-light);
}

.prop-input[type="color"] {
  padding: 2px;
  height: 30px;
  cursor: pointer;
}

.prop-select {
  flex: 1;
  padding: 5px 8px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-family: var(--font);
  color: var(--text-primary);
  background: var(--bg-primary);
  cursor: pointer;
}

.prop-delete-btn {
  width: 100%;
  padding: 8px;
  border: 1px solid var(--danger);
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--danger);
  font-size: 13px;
  font-family: var(--font);
  cursor: pointer;
  margin-top: 12px;
  transition: all 0.15s ease;
}

.prop-delete-btn:hover {
  background: var(--danger);
  color: white;
}

/* Overview Panel */
.overview-panel {
  position: absolute;
  bottom: 16px;
  left: 16px;
  width: 240px;
  height: 240px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.overview-panel.hidden {
  display: none;
}

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

.overview-label {
  position: absolute;
  top: 8px;
  right: 8px;
  font-size: 10px;
  font-weight: 600;
  color: var(--text-secondary);
  background: rgba(255, 255, 255, 0.8);
  padding: 2px 6px;
  border-radius: 4px;
}

/* Dragging ghost cursor */
.drag-ghost {
  position: fixed;
  pointer-events: none;
  z-index: 1000;
  opacity: 0.7;
  background: var(--bg-secondary);
  border: 1px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: 4px 10px;
  font-size: 12px;
  color: var(--accent);
  box-shadow: var(--shadow-lg);
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-secondary);
}