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

:root {
  --bg: #090909;
  --bg-panel: #151515;
  --bg-panel-soft: #1b1b1b;
  --border-subtle: #252525;
  --accent: #4ea1ff;
  --accent-soft: #26384a;
  --text: #f5f5f5;
  --text-muted: #a0a0a0;
  --radius: 10px;
  --shadow-soft: 0 18px 50px rgba(0, 0, 0, 0.65);
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: radial-gradient(circle at top, #1b1b1b 0, #050505 55%);
  color: var(--text);
  overflow: hidden;
  font-size: 15px;
}

#viewer {
  width: 100vw;
  height: 100vh;
}

/* Google icons base */
.material-symbols-outlined {
  font-variation-settings:
    'FILL' 0,
    'wght' 400,
    'GRAD' 0,
    'opsz' 24;
  line-height: 1;
}

/* Sidebar */
#sidebar {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 320px;
  background: rgba(10, 10, 10, 0.96);
  border-left: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  backdrop-filter: blur(22px);
  box-shadow: var(--shadow-soft);
  z-index: 20;
  transition: transform 0.25s ease;
  overflow: hidden;
}

/* Horizontal resize handle */
#sidebarResizeHandle {
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  cursor: col-resize;
  z-index: 2;
  background: transparent;
}

/* Sidebar header */
#sidebarHeader {
  padding: 12px 14px 10px;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  gap: 10px;
}

/* Parts list */
#partsList {
  flex: 1 1 auto;
  overflow-y: auto;
  padding: 12px 12px 12px;
  font-size: 13px;
}

/* Generic panels under parts list */
.sidebar-panel {
  flex: 0 0 auto;
  padding: 8px 12px 10px;
  border-top: 1px solid var(--border-subtle);
  background: rgba(12, 12, 12, 0.98);
  display: block;
  font-size: 12px;
  position: relative;
  overflow-y: auto;
}

#scenePanel,
#advancedPanel {
  min-height: 120px;
  max-height: calc(100vh - 260px); /* leave room for header/parts */
  overflow-y: auto;
}

#scenePanel {
  height: 220px; /* sensible default, user can resize */
}

#advancedPanel {
  display: none;
  height: 435px; /* start tall enough to show full transform controls */
}

/* Vertical resize handles for panels */
.panel-resize-handle {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  cursor: row-resize;
  z-index: 2;
  background: transparent;
}

/* Category UI in parts list */
.parts-category {
  margin-top: 8px;
}

.parts-category-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 4px 2px;
  cursor: pointer;
  color: var(--text-muted);
  font-size: 12px;
}

.parts-category-title {
  font-weight: 500;
}

.category-toggle {
  background: none;
  border: none;
  padding: 2px;
  border-radius: 999px;
  cursor: pointer;
  color: var(--text-muted);
  display: flex;
  align-items: center;
}

.category-toggle:hover {
  background: #202020;
  color: var(--text);
}

.parts-category-body.collapsed {
  display: none;
}

.toolbar-row {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
}

.toolbar-row.compact {
  font-size: 12px;
  color: var(--text-muted);
  justify-content: space-between;
}

#sidebar button {
  cursor: pointer;
  padding: 7px 14px;
  border-radius: 999px;
  border: 1px solid var(--border-subtle);
  background: var(--bg-panel-soft);
  color: var(--text);
  font-size: 13px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

#sidebar button:hover:not(:disabled) {
  background: #262626;
  border-color: #3a3a3a;
}

.btn-primary {
  border-color: var(--accent-soft);
  background: linear-gradient(135deg, #253347, #151515);
}

.btn-pill {
  padding-inline: 16px;
}

#fileName {
  max-width: 100%;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  font-size: 12px;
  color: var(--text-muted);
}

/* Section label / header */
.section-label {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  opacity: 0.9;
}

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

.parts-header-row span {
  font-size: 12px;
  color: var(--text-muted);
}

/* Part items */
.part-item {
  padding: 5px 6px;
  margin-bottom: 9px;
  border-radius: var(--radius);
  background: var(--bg-panel-soft);
  border: 1px solid var(--border-subtle);
  cursor: grab;
  user-select: none;
  display: flex;
  align-items: center;
  gap: 10px;
  transition: background 0.15s ease, border-color 0.15s ease, transform 0.1s ease;
}

.part-item:hover {
  background: #252525;
  border-color: #353535;
  transform: translateY(-1px);
}

.part-item:active {
  cursor: grabbing;
  transform: translateY(0);
}

.part-preview {
  width: 52px;
  height: 52px;
  border-radius: 9px;
  background: radial-gradient(circle at top, #333 0, #111 65%);
  flex-shrink: 0;
  overflow: hidden;
}

.part-name {
  flex: 1;
  font-size: 12px;
  line-height: 1.3;
  word-break: break-word;
}

/* Left toolbar */
#leftToolbar {
  position: fixed;
  top: 50%;
  left: 18px;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 14px;
  z-index: 30;
}

.icon-btn {
  width: 52px;
  height: 52px;
  border-radius: 999px;
  border: 1px solid var(--border-subtle);
  background: rgba(10, 10, 10, 0.95);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text);
  cursor: pointer;
  box-shadow: var(--shadow-soft);
  transition: background 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.icon-btn.small-icon .material-symbols-outlined {
  font-size: 26px;
}

.icon-btn.large .material-symbols-outlined {
  font-size: 32px;
}

.icon-btn:disabled {
  opacity: 0.35;
  cursor: default;
}

.icon-btn.active {
  border-color: var(--accent-soft);
  color: var(--accent);
  background: rgba(45, 45, 45, 0.95);
}

.icon-btn.large {
  width: 64px;
  height: 64px;
}

/* Bottom controls */
#bottomControls {
  position: fixed;
  bottom: 28px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 14px;
  z-index: 25;
}

#controlsRow {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 18px;
}

.controls-group {
  display: none;
  gap: 18px;
  align-items: center;
}

#measurementReadout {
  display: none;
  padding: 10px 18px;
  border-radius: 14px;
  background: rgba(10, 10, 10, 0.88);
  border: 1px solid rgba(78, 161, 255, 0.6);
  color: var(--text);
  font-size: 13px;
  line-height: 1.3;
  min-width: 160px;
  text-align: center;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.55);
}

#measurementReadout.visible {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

#rotationModeBtn {
  background: rgba(20, 20, 20, 0.95);
  border-color: #3a3a3a;
}

#rotationModeBtn.active {
  background: rgba(45, 45, 45, 0.95);
  border-color: var(--accent-soft);
  color: var(--accent);
}

/* Advanced panel shared elements */
.advanced-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 6px;
}

.advanced-selection-label {
  font-size: 11px;
  color: var(--text-muted);
}

.advanced-subtitle {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-top: 6px;
  margin-bottom: 4px;
}

.advanced-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 6px;
}

.advanced-grid.snap-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.advanced-grid.snap-grid .advanced-field.span-2 {
  grid-column: 1 / -1;
}

.advanced-field {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.advanced-field.flip-field {
  grid-column: 1 / -1;
}

.advanced-field span {
  font-size: 10px;
  color: var(--text-muted);
}

.advanced-field input {
  width: 100%;
  padding: 6px 8px;
  border-radius: 6px;
  border: 1px solid var(--border-subtle);
  background: #141414;
  color: var(--text);
  font-size: 12px;
  line-height: 1.4;
}

.flip-toggle-group {
  display: flex;
  gap: 6px;
}

.flip-toggle {
  flex: 1;
  padding: 6px 0;
  border-radius: 6px;
  border: 1px solid var(--border-subtle);
  background: #141414;
  color: var(--text-muted);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.flip-toggle:hover:not(:disabled) {
  background: #1c1c1c;
  color: var(--text);
}

.flip-toggle:disabled {
  opacity: 0.4;
  cursor: default;
}

.flip-toggle.active {
  background: rgba(78, 161, 255, 0.16);
  border-color: var(--accent);
  color: var(--accent);
}

.advanced-field input:disabled {
  opacity: 0.4;
  cursor: default;
}

/* Scene objects list */
.scene-objects-list {
  margin-top: 4px;
}

.scene-object-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 4px 0;
  font-size: 11px;
  border-bottom: 1px solid rgba(37, 37, 37, 0.5);
  cursor: pointer;
}

.scene-object-row:last-child {
  border-bottom: none;
}

.scene-object-name {
  flex: 1;
  margin-right: 6px;
  color: var(--text-muted);
}

.scene-object-row.selected .scene-object-name {
  color: var(--accent);
}

.scene-object-actions {
  display: inline-flex;
  gap: 4px;
}

.scene-object-btn {
  border-radius: 999px;
  border: 1px solid var(--border-subtle);
  background: #171717;
  color: var(--text-muted);
  padding: 2px 4px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

.scene-object-btn .material-symbols-outlined {
  font-size: 16px;
}

.scene-object-btn:hover {
  background: #232323;
  color: var(--accent);
}

/* Selection context menu */
#selectionContextMenu {
  position: fixed;
  inset: auto;
  min-width: 180px;
  background: rgba(12, 12, 12, 0.98);
  border: 1px solid var(--border-subtle);
  border-radius: 10px;
  box-shadow: var(--shadow-soft);
  padding: 6px 0;
  display: none;
  z-index: 60;
}

.context-menu-item {
  width: 100%;
  border: none;
  background: transparent;
  color: var(--text);
  text-align: left;
  padding: 8px 14px;
  font-size: 13px;
  cursor: pointer;
}

.context-menu-item:hover:not(:disabled) {
  background: var(--accent-soft);
  color: var(--text);
}

.context-menu-item:disabled {
  color: var(--text-muted);
  cursor: default;
}

.context-menu-item:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.context-menu-separator {
  height: 1px;
  background: var(--border-subtle);
  margin: 4px 0;
}

/* Help overlay */
#helpOverlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 40;
}

#helpOverlay.open {
  display: flex;
}

#helpPanel {
  width: min(550px, 92vw);
  max-height: 90vh;
  background: #121212;
  border-radius: 16px;
  border: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-soft);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  font-size: 13px;
}

.help-header {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.help-header h2 {
  font-size: 16px;
  font-weight: 600;
}

#helpCloseBtn {
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 18px;
}

.help-content {
  padding: 10px 16px 14px;
  font-size: 12px;
  color: var(--text-muted);
  overflow-y: auto;
}

.help-section-title {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: 8px;
  margin-bottom: 4px;
  color: var(--text);
}

.help-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 2.2fr);
  gap: 4px 12px;
  margin-bottom: 6px;
}

.help-key {
  font-family: monospace;
  font-size: 11px;
  padding: 2px 4px;
  border-radius: 4px;
  background: #1f1f1f;
  color: var(--text);
  text-align: center;
  white-space: nowrap;
}

.help-desc {
  font-size: 11px;
  line-height: 1.4;
}

/* Sidebar mobile behavior */
@media (max-width: 820px) {
  #sidebar {
    width: 280px;
    transform: translateX(100%);
  }

  #sidebar.open {
    transform: translateX(0);
  }

  #sidebarResizeHandle {
    display: none;
  }
}

@media (min-width: 821px) {
  #sidebar {
    transform: translateX(0);
  }
}

@media (max-width: 600px) {
  #partsList {
    padding: 8px;
  }

  .part-item {
    margin-bottom: 7px;
  }

  #leftToolbar {
    left: 12px;
  }
}