/* 装配图工具栏、页签、主视口与画布 */
/* ==================== 交互式装配图查看器 (Interactive Assembly Drawing) ==================== */
#sheet {
  display: none;
  position: absolute;
  top: 0; left: 0; width: 100%; height: 100%;
  flex-direction: column;
  background: #11141a;
  overflow: hidden;
  z-index: 10;
  padding: 0;
}
body.sheet-mode #sheet {
  display: flex !important;
}
/* 隐藏 3D 专属工具条按钮（当处于装配图时） */
body.sheet-mode #bAsm,
body.sheet-mode #bExp,
body.sheet-mode #exp,
body.sheet-mode #cam,
body.sheet-mode #bWire,
body.sheet-mode #bXRay,
body.sheet-mode #bScr,
body.sheet-mode #bHarn,
body.sheet-mode #bEnv,
body.sheet-mode #bFit {
  display: none !important;
}
body.sheet-mode footer #footModel { display: none !important; }
body.sheet-mode footer #footSheet { display: inline !important; }

/* 顶部装配图工具栏 */
#sheetToolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  background: var(--pan);
  border-bottom: 1px solid var(--line);
  flex: none;
  min-height: 40px;
  overflow-x: auto;
  white-space: nowrap;
}
.sheet-tabs {
  display: flex;
  gap: 5px;
  align-items: center;
}
.sheet-tab {
  background: var(--pan2);
  color: var(--tx);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 4px 10px;
  font-size: 12px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  transition: all .15s ease;
}
.sheet-tab:hover {
  border-color: var(--ac);
  color: #fff;
}
.sheet-tab.on {
  background: #1e3a66;
  border-color: var(--ac);
  color: #fff;
  font-weight: 600;
  box-shadow: 0 0 10px rgba(76,154,255,.25);
}
.sheet-tab.guide-tab {
  background: rgba(245, 158, 11, 0.12);
  border-color: rgba(245, 158, 11, 0.4);
  color: #f59e0b;
}
.sheet-tab.guide-tab.on {
  background: #78350f;
  border-color: #f59e0b;
  color: #fef3c7;
  box-shadow: 0 0 10px rgba(245, 158, 11, 0.35);
}

.sheet-vsep {
  width: 1px;
  height: 20px;
  background: var(--line);
  margin: 0 4px;
  flex: none;
}
.sheet-btn-group {
  display: flex;
  border: 1px solid var(--line);
  border-radius: 5px;
  overflow: hidden;
  flex: none;
}
.sheet-btn-group .sheet-btn {
  border: none;
  border-radius: 0;
  padding: 3px 8px;
  font-size: 11.5px;
  background: var(--pan2);
  border-right: 1px solid var(--line);
  cursor: pointer;
}
.sheet-btn-group .sheet-btn:last-child {
  border-right: none;
}
.sheet-btn-group .sheet-btn.on {
  background: var(--ac);
  color: #fff;
  font-weight: 600;
}
.sheet-layers {
  display: flex;
  gap: 8px;
  align-items: center;
  font-size: 11.5px;
  color: var(--dim);
}
.sheet-layers label {
  display: inline-flex;
  align-items: center;
  gap: 3px;
  cursor: pointer;
  -webkit-user-select: none;
  user-select: none;
}
.sheet-layers input[type=checkbox] {
  accent-color: var(--ac);
  cursor: pointer;
}
.sheet-space {
  flex: 1;
  min-width: 8px;
}
.sheet-btn-accent {
  background: linear-gradient(135deg, #1d4ed8, #2563eb);
  color: #fff;
  border: 1px solid #60a5fa;
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px 10px;
  border-radius: 5px;
  cursor: pointer;
  transition: all .15s;
}
.sheet-btn-accent:hover {
  background: linear-gradient(135deg, #2563eb, #3b82f6);
  box-shadow: 0 0 12px rgba(96,165,250,.4);
}

/* 主视口区域 */
#sheetViewport {
  position: relative;
  flex: 1;
  min-height: 0;
  overflow: hidden;
  cursor: grab;
  background: #0f1217;
  transition: background 0.2s;
}
#sheetViewport.is-dragging {
  cursor: grabbing !important;
}

/* 画布与缩放平移 */
#sheetCanvas {
  position: absolute;
  top: 0; left: 0;
  transform-origin: 0 0;
  will-change: transform;
}
#sheetSvgWrapper {
  display: inline-block;
  vertical-align: top;
  box-shadow: 0 8px 32px rgba(0,0,0,.5);
  border-radius: 6px;
  overflow: hidden;
  transition: box-shadow 0.2s;
}
#sheetSvgWrapper svg {
  display: block;
  border-radius: 6px;
}