:root {
  --bg-page: #f1f5f9;
  --bg-panel: #ffffff;
  --bg-card: #f8fafc;
  --bg-card-hover: #f1f5f9;
  --bg-card-active: #eff6ff;
  --border-color: #e2e8f0;
  --border-active: #2563eb;
  --text-main: #0f172a;
  --text-muted: #475569;
  --text-light: #64748b;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-soft: #dbeafe;
  --success: #059669;
  --success-hover: #047857;
  --radius-sm: 6px;
  --radius-md: 10px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.08);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-page);
  color: var(--text-main);
  line-height: 1.45;
  font-size: 14px;
  overflow-x: hidden;
}

.hidden {
  display: none !important;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
}

/* Header */
.app-header {
  background: var(--bg-panel);
  border-bottom: 1px solid var(--border-color);
  padding: 10px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
  position: sticky;
  top: 0;
  z-index: 40;
  box-shadow: var(--shadow-sm);
}

.brand-block {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-icon {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #2563eb, #1d4ed8);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  flex-shrink: 0;
  box-shadow: 0 2px 6px rgba(37, 99, 235, 0.25);
}

.brand-title h1 {
  font-size: 16px;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-main);
}

.brand-title p {
  font-size: 11.5px;
  color: var(--text-muted);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font-size: 12.5px;
  font-weight: 700;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.btn-success {
  background: var(--success);
  color: #ffffff;
  box-shadow: 0 1px 3px rgba(5, 150, 105, 0.3);
}

.btn-success:hover {
  background: var(--success-hover);
}

.btn-primary {
  background: var(--primary);
  color: #ffffff;
  box-shadow: 0 1px 3px rgba(37, 99, 235, 0.3);
}

.btn-primary:hover {
  background: var(--primary-hover);
}

.btn-accent {
  background: #0f172a;
  color: #ffffff;
}

.btn-accent:hover {
  background: #1e293b;
}

.btn-secondary {
  background: #ffffff;
  color: var(--text-main);
  border-color: #cbd5e1;
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: #94a3b8;
}

.btn-mini {
  padding: 5px 10px;
  font-size: 11.5px;
  font-weight: 700;
  border-radius: 5px;
  border: 1px solid #cbd5e1;
  background: #fff;
  color: var(--text-main);
  cursor: pointer;
}

.btn-mini:hover {
  background: var(--bg-card-hover);
}

/* Main Grid */
.app-layout {
  display: grid;
  grid-template-columns: 390px 1fr;
  gap: 16px;
  padding: 14px 18px;
  max-width: 1660px;
  margin: 0 auto;
  align-items: start;
}

.sidebar {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.section-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 13px;
  box-shadow: var(--shadow-sm);
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 10px;
  padding-bottom: 7px;
  border-bottom: 1px solid #f1f5f9;
}

.section-title {
  font-size: 13.5px;
  font-weight: 800;
  color: var(--text-main);
}

.section-badge {
  font-size: 11px;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 99px;
  background: var(--primary-soft);
  color: var(--primary-hover);
}

/* Upload & Demo Models */
.upload-box {
  margin-bottom: 10px;
}

.upload-btn-label {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  width: 100%;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  border: 1.5px dashed #3b82f6;
  background: #eff6ff;
  color: #1d4ed8;
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
}

.upload-btn-label:hover {
  background: #dbeafe;
}

.upload-status {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
  text-align: center;
}

.sub-label {
  font-size: 11.5px;
  font-weight: 700;
  color: var(--text-main);
  display: block;
}

.demo-models-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: 6px;
}

.demo-model-btn {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 7px 9px;
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--border-color);
  background: var(--bg-card);
  cursor: pointer;
  text-align: left;
  transition: all 0.14s ease;
}

.demo-model-btn:hover {
  border-color: #94a3b8;
  background: var(--bg-card-hover);
}

.demo-model-btn.active {
  border-color: var(--primary);
  background: var(--bg-card-active);
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.12);
}

.demo-thumb-img {
  width: 48px;
  height: 36px;
  object-fit: cover;
  border-radius: 4px;
  border: 1px solid rgba(15, 23, 42, 0.15);
  flex-shrink: 0;
}

.demo-model-meta {
  min-width: 0;
  flex: 1;
}

.demo-model-title {
  font-size: 12px;
  font-weight: 800;
  color: var(--text-main);
  line-height: 1.2;
}

.demo-model-cat {
  font-size: 10.5px;
  font-weight: 600;
  color: var(--primary-hover);
  margin-top: 1px;
}

/* Mode Switch (Custom cm/mm vs Scale 1:1) */
.mode-switch-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  margin-bottom: 10px;
}

.mode-switch-btn {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 7px 9px;
  border-radius: var(--radius-sm);
  border: 1.5px solid #cbd5e1;
  background: #ffffff;
  cursor: pointer;
  text-align: left;
}

.mode-switch-btn.active {
  border-color: var(--primary);
  background: #eff6ff;
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.12);
}

.mode-btn-title {
  font-size: 11.5px;
  font-weight: 800;
  color: var(--text-main);
}

.mode-btn-sub {
  font-size: 10px;
  color: var(--text-muted);
}

.presets-wrap {
  background: #f8fafc;
  padding: 8px;
  border-radius: var(--radius-sm);
  border: 1px solid #e2e8f0;
  margin-bottom: 8px;
}

.presets-label {
  display: block;
  font-size: 11px;
  font-weight: 700;
  color: var(--text-muted);
  margin-bottom: 5px;
}

.preset-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
}

.chip-btn {
  font-size: 11px;
  font-weight: 700;
  padding: 4px 8px;
  border-radius: 999px;
  border: 1px solid #cbd5e1;
  background: #fff;
  color: var(--text-main);
  cursor: pointer;
}

.chip-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.chip-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.unit-toggle-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 11.5px;
  font-weight: 700;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.unit-pills {
  display: flex;
  gap: 4px;
}

.unit-pill {
  padding: 3px 8px;
  font-size: 11px;
  font-weight: 700;
  border-radius: 99px;
  border: 1px solid #cbd5e1;
  background: #fff;
  cursor: pointer;
}

.unit-pill.active {
  background: #0f172a;
  color: #fff;
  border-color: #0f172a;
}

.control-group {
  margin-top: 9px;
}

.control-label-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 4px;
}

.control-label-row label {
  font-size: 12px;
  font-weight: 700;
  color: var(--text-main);
}

.control-unit {
  font-size: 11px;
  color: var(--text-light);
  font-weight: 600;
}

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

.control-inputs input[type="range"] {
  flex: 1;
  accent-color: var(--primary);
  cursor: pointer;
}

.number-box {
  display: flex;
  align-items: center;
  background: #fff;
  border: 1px solid #cbd5e1;
  border-radius: var(--radius-sm);
  padding: 3px 7px;
  width: 86px;
  flex-shrink: 0;
}

.number-box.full-w {
  width: 100%;
  margin-top: 4px;
}

.number-box input[type="number"] {
  width: 100%;
  border: none;
  outline: none;
  font-size: 12.5px;
  font-weight: 700;
  color: var(--text-main);
  text-align: right;
  background: transparent;
}

.number-box span {
  font-size: 11px;
  color: var(--text-light);
  margin-left: 3px;
  font-weight: 600;
}

.two-col-controls {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-top: 8px;
  align-items: center;
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 11.5px;
  font-weight: 700;
  color: var(--text-main);
  cursor: pointer;
}

.form-select {
  width: 100%;
  margin-top: 3px;
  padding: 6px 8px;
  border-radius: var(--radius-sm);
  border: 1px solid #cbd5e1;
  background: #ffffff;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-main);
}

.scale-1to1-info-box {
  background: #ecfdf5;
  border: 1px solid #10b981;
  color: #065f46;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  font-size: 11.5px;
  margin-bottom: 8px;
}

.scale-1to1-info-box p {
  margin-top: 3px;
  font-size: 11px;
}

.helper-note {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 4px;
  line-height: 1.3;
}

/* Main Workspace Right */
.workspace-main {
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-width: 0;
}

.stats-banner {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  box-shadow: var(--shadow-sm);
}

.stats-cards-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.stat-card {
  padding: 9px 11px;
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
}

.stat-card-highlight {
  background: linear-gradient(135deg, #eff6ff, #dbeafe);
  border-color: #93c5fd;
}

.stat-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--text-muted);
}

.stat-value {
  font-size: 18px;
  font-weight: 900;
  color: var(--text-main);
  margin-top: 2px;
}

.stat-card-highlight .stat-value {
  color: #1e3a8a;
}

.stat-sub {
  font-size: 11px;
  color: var(--text-muted);
  margin-top: 2px;
  font-weight: 600;
}

.orientation-tip {
  margin-top: 9px;
  padding: 7px 11px;
  border-radius: var(--radius-sm);
  background: #f8fafc;
  border: 1px solid #cbd5e1;
  font-size: 12px;
  font-weight: 700;
  color: #1e3a8a;
}

/* Viewer Toolbar */
.viewer-toolbar {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 8px 10px;
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
}

.view-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.view-tab {
  padding: 7px 11px;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  background: transparent;
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
}

.view-tab:hover {
  background: var(--bg-card-hover);
  color: var(--text-main);
}

.view-tab.active {
  background: var(--primary);
  color: #ffffff;
}

.sheet-navigator {
  display: flex;
  align-items: center;
  gap: 6px;
  background: #f8fafc;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  border: 1px solid #e2e8f0;
}

.nav-label {
  font-size: 11.5px;
  font-weight: 700;
  color: var(--text-muted);
}

.tile-select {
  padding: 4px 8px;
  border-radius: 5px;
  border: 1px solid #cbd5e1;
  font-size: 12px;
  font-weight: 800;
  color: var(--primary-hover);
  background: #fff;
}

/* Stage Grid */
.stage-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 14px;
}

.stage-grid.single-panel-mode {
  grid-template-columns: 1fr;
}

.stage-panel {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
}

.stage-panel-header {
  padding: 10px 14px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  background: #f8fafc;
}

.stage-panel-header h2 {
  font-size: 13.5px;
  font-weight: 800;
  color: var(--text-main);
}

.stage-panel-header p {
  font-size: 11px;
  color: var(--text-muted);
}

.file-tag {
  font-size: 11px;
  font-weight: 800;
  padding: 3px 9px;
  border-radius: 99px;
  white-space: nowrap;
}

.file-tag-map {
  background: #dbeafe;
  color: #1e40af;
}

.file-tag-sheet {
  background: #dcfce7;
  color: #166534;
}

.stage-canvas-wrap {
  padding: 14px;
  background: #e2e8f0;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 530px;
}

.stage-canvas-wrap.sheet-paper-bg {
  background: #cbd5e1;
}

.stage-canvas-wrap svg {
  width: 100%;
  max-width: 560px;
  height: auto;
  background: #fff;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.16);
  border-radius: 4px;
}

.stage-grid.single-panel-mode .stage-canvas-wrap svg {
  max-width: 740px;
}

@media (max-width: 1100px) {
  .app-layout {
    grid-template-columns: 1fr;
  }

  .stats-cards-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .stage-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .app-header {
    padding: 10px 12px;
  }

  .app-layout {
    padding: 10px 12px;
  }

  .stats-cards-grid {
    grid-template-columns: 1fr;
  }

  .mode-switch-grid {
    grid-template-columns: 1fr;
  }

  .header-actions .btn {
    width: 100%;
  }
}