@property --ac1 {
      syntax: '<color>';
      inherits: true;
      initial-value: #22d3ee;
    }

    @property --ac2 {
      syntax: '<color>';
      inherits: true;
      initial-value: #4c8dff;
    }

    :root {
      --bg-deep: #030712;
      --bg-base: #060b1e;
      --bg-elevated: #0c1433;
      --panel: rgba(14, 25, 58, 0.65);
      --panel-solid: #0d1738;
      --panel-hover: rgba(22, 38, 86, 0.85);
      --line: rgba(120, 180, 255, 0.18);
      --line-bright: rgba(120, 200, 255, 0.45);
      --text: #f0f6fc;
      --text-muted: #8ca2cc;
      --text-dim: #556c9a;

      --cyan: #22d3ee;
      --blue: #3b82f6;
      --indigo: #6366f1;
      --purple: #a855f7;
      --pink: #ec4899;
      --amber: #f59e0b;
      --green: #10b981;
      --red: #ef4444;

      --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
      --ease-in-out: cubic-bezier(0.65, 0, 0.35, 1);
      --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);

      --shadow-glow: 0 0 30px rgba(34, 211, 238, 0.25);
      --shadow-card: 0 10px 30px -10px rgba(0, 0, 0, 0.5), 0 0 1px 1px rgba(255, 255, 255, 0.05);
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      -webkit-tap-highlight-color: transparent;
    }

    html,
    body {
      height: 100%;
      overflow: hidden;
      background: var(--bg-deep);
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      color: var(--text);
      user-select: none;
    }

    /* 动态流光背景 */
    #ambient-canvas {
      position: fixed;
      inset: 0;
      z-index: 0;
      pointer-events: none;
      opacity: 0.65;
    }

    .noise-overlay {
      position: fixed;
      inset: 0;
      z-index: 1;
      pointer-events: none;
      opacity: 0.03;
      background-image: radial-gradient(rgba(255, 255, 255, 0.8) 1px, transparent 0);
      background-size: 24px 24px;
    }

    /* 顶栏信息 */
    #top-bar {
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      height: 56px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0 28px;
      z-index: 50;
      background: linear-gradient(180deg, rgba(6, 11, 30, 0.85) 0%, transparent 100%);
      backdrop-filter: blur(8px);
    }

    .brand {
      display: flex;
      align-items: center;
      gap: 10px;
      font-size: 14px;
      font-weight: 700;
      letter-spacing: 0.05em;
      color: var(--text-muted);
    }

    .brand-badge {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      background: var(--cyan);
      box-shadow: 0 0 10px var(--cyan);
    }

    .chapter-tag {
      font-size: 13px;
      color: var(--text-dim);
      border-left: 1px solid var(--line);
      padding-left: 10px;
    }

    .unit-info {
      font-size: 13px;
      font-weight: 600;
      color: var(--cyan);
      background: rgba(34, 211, 238, 0.1);
      border: 1px solid rgba(34, 211, 238, 0.25);
      border-radius: 20px;
      padding: 4px 14px;
    }

    /* 顶部进度条 */
    #progress-bar {
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      height: 3px;
      z-index: 60;
      background: rgba(255, 255, 255, 0.05);
    }

    #progress-fill {
      height: 100%;
      width: 0%;
      background: linear-gradient(90deg, var(--cyan), var(--blue), var(--purple));
      box-shadow: 0 0 12px var(--cyan);
      transition: width 0.4s var(--ease-out);
    }

    /* 主讲台视口 */
    #viewport {
      position: relative;
      width: 100vw;
      height: 100vh;
      height: 100dvh;
      overflow: hidden;
      z-index: 10;
    }

    .slide {
      position: absolute;
      inset: 0;
      padding: 82px 6vw 132px;
      overflow-y: auto;
      overflow-x: hidden;
      opacity: 0;
      pointer-events: none;
      transform: translate3d(0, 24px, 0) scale(0.98);
      transition: opacity 0.5s var(--ease-out), transform 0.5s var(--ease-out);
    }

    .slide.active {
      opacity: 1;
      pointer-events: auto;
      transform: translate3d(0, 0, 0) scale(1);
    }

    .slide.prev-slide {
      transform: translate3d(0, -24px, 0) scale(0.98);
    }

    .slide::-webkit-scrollbar {
      width: 6px;
    }

    .slide::-webkit-scrollbar-thumb {
      background: rgba(255, 255, 255, 0.15);
      border-radius: 3px;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      min-height: 100%;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }

    /* 标题系统 */
    .section-header {
      margin-bottom: 24px;
      flex-shrink: 0;
    }

    .tag-line {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      font-size: 12px;
      font-weight: 800;
      letter-spacing: 0.15em;
      text-transform: uppercase;
      color: var(--cyan);
      margin-bottom: 8px;
    }

    .tag-line::before {
      content: "";
      width: 16px;
      height: 2px;
      background: currentColor;
      border-radius: 1px;
    }

    .slide-title {
      font-size: clamp(24px, 2.8vw, 36px);
      font-weight: 800;
      letter-spacing: -0.02em;
      line-height: 1.25;
      color: #fff;
    }

    .slide-desc {
      margin-top: 6px;
      font-size: 15px;
      color: var(--text-muted);
      line-height: 1.6;
    }

    .gradient-text {
      background: linear-gradient(120deg, #fff 20%, var(--cyan) 70%, var(--blue) 100%);
      background-clip: text;
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    /* 卡片系统 */
    .card {
      background: var(--panel);
      border: 1px solid var(--line);
      border-radius: 20px;
      padding: 24px;
      backdrop-filter: blur(12px);
      box-shadow: var(--shadow-card);
      position: relative;
      overflow: hidden;
      transition: transform 0.3s var(--ease-out), border-color 0.3s var(--ease-out), box-shadow 0.3s var(--ease-out);
    }

    .card:hover {
      border-color: var(--line-bright);
      box-shadow: 0 16px 40px -12px rgba(0, 0, 0, 0.6), 0 0 20px rgba(34, 211, 238, 0.12);
    }

    .card-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin-bottom: 16px;
    }

    .card-title {
      font-size: 18px;
      font-weight: 700;
      color: #fff;
      display: flex;
      align-items: center;
      gap: 10px;
    }

    .badge {
      font-size: 12px;
      font-weight: 700;
      padding: 4px 10px;
      border-radius: 999px;
      background: rgba(255, 255, 255, 0.06);
      border: 1px solid var(--line);
      color: var(--text-muted);
    }

    /* 按钮控件 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      padding: 10px 20px;
      border-radius: 12px;
      font-size: 14px;
      font-weight: 700;
      border: 1px solid var(--line);
      background: rgba(255, 255, 255, 0.05);
      color: #fff;
      cursor: pointer;
      transition: all 0.25s var(--ease-out);
      outline: none;
      font-family: inherit;
    }

    .btn:hover {
      background: rgba(255, 255, 255, 0.12);
      border-color: var(--line-bright);
      transform: translateY(-2px);
    }

    .btn:active {
      transform: translateY(0);
    }

    .btn-primary {
      background: linear-gradient(135deg, var(--cyan), var(--blue));
      border: none;
      color: #020617;
      box-shadow: 0 4px 14px rgba(34, 211, 238, 0.3);
    }

    .btn-primary:hover {
      background: linear-gradient(135deg, #38bdf8, #2563eb);
      box-shadow: 0 6px 20px rgba(34, 211, 238, 0.45);
      color: #020617;
    }

    .btn-danger {
      background: linear-gradient(135deg, #f87171, #dc2626);
      border: none;
      color: #fff;
    }

    /* 网格系统 */
    .grid-2 {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 20px;
    }

    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 20px;
    }

    @media (max-width: 960px) {

      .grid-2,
      .grid-3 {
        grid-template-columns: 1fr;
      }
    }

    /* 底部操作与导航悬浮条 */
    #dock {
      position: fixed;
      bottom: 24px;
      left: 50%;
      transform: translateX(-50%);
      display: flex;
      align-items: center;
      gap: 6px;
      padding: 7px 12px;
      border-radius: 18px;
      z-index: 90;
      background: rgba(8, 14, 34, 0.82);
      border: 1px solid var(--line-bright);
      backdrop-filter: blur(20px);
      box-shadow: 0 16px 40px rgba(0, 0, 0, 0.6), 0 0 1px 1px rgba(255, 255, 255, 0.1);
      transition: all 0.3s var(--ease-out);
    }

    #dock:hover {
      box-shadow: 0 20px 48px rgba(0, 0, 0, 0.75), 0 0 24px rgba(34, 211, 238, 0.2);
    }

    .dock-btn {
      width: 38px;
      height: 38px;
      border-radius: 11px;
      border: 1px solid transparent;
      background: rgba(255, 255, 255, 0.04);
      color: var(--text-muted);
      display: grid;
      place-items: center;
      line-height: 0;
      padding: 0;
      cursor: pointer;
      transition: background-color 0.2s var(--ease-out), border-color 0.2s var(--ease-out),
        color 0.2s var(--ease-out), box-shadow 0.2s var(--ease-out), transform 0.2s var(--ease-out);
      outline: none;
      position: relative;
    }

    /* 统一描边图标，居中由 grid 保证，不受字体基线影响 */
    .dock-btn svg {
      width: 20px;
      height: 20px;
      display: block;
      pointer-events: none;
    }

    .dock-btn:hover {
      background: rgba(34, 211, 238, 0.14);
      border-color: var(--line-bright);
      color: var(--cyan);
      transform: translateY(-2px);
      box-shadow: 0 3px 12px rgba(34, 211, 238, 0.25);
    }

    .dock-btn:active {
      transform: translateY(0) scale(0.95);
    }

    .dock-btn.active {
      background: rgba(34, 211, 238, 0.22);
      border-color: var(--cyan);
      color: var(--cyan);
      box-shadow: 0 0 14px rgba(34, 211, 238, 0.35);
    }

    .dock-btn:disabled {
      opacity: 0.25;
      pointer-events: none;
    }

    .dock-divider {
      width: 1px;
      height: 22px;
      background: var(--line);
      margin: 0 3px;
      flex: 0 0 auto;
    }

    #page-indicator {
      font-size: 13px;
      font-weight: 800;
      color: #fff;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 5px;
      font-variant-numeric: tabular-nums;
      border-radius: 999px;
      padding: 6px 12px;
      line-height: 1;
      transition: all 0.2s;
    }

    #page-indicator:hover {
      background: rgba(255, 255, 255, 0.08);
      color: var(--cyan);
    }

    /* 翻页预览浮窗 */
    #page-preview-popover {
      position: absolute;
      bottom: calc(100% + 14px);
      left: 50%;
      transform: translateX(-50%) translateY(8px) scale(0.95);
      background: rgba(12, 20, 51, 0.95);
      border: 1px solid var(--line-bright);
      border-radius: 14px;
      padding: 10px 14px;
      box-shadow: 0 16px 36px rgba(0, 0, 0, 0.6);
      pointer-events: none;
      opacity: 0;
      transition: all 0.2s var(--ease-out);
      white-space: nowrap;
      z-index: 95;
    }

    #page-preview-popover.show {
      opacity: 1;
      transform: translateX(-50%) translateY(0) scale(1);
    }

    .preview-num {
      font-size: 11px;
      font-weight: 800;
      color: var(--cyan);
    }

    .preview-title {
      font-size: 13px;
      font-weight: 700;
      color: #fff;
      margin-top: 2px;
    }

    /* 左右侧悬浮翻页快击区域 */
    .nav-edge-arrow {
      position: fixed;
      top: 50%;
      transform: translateY(-50%);
      width: 48px;
      height: 96px;
      display: grid;
      place-items: center;
      z-index: 40;
      cursor: pointer;
      background: rgba(8, 14, 34, 0.45);
      backdrop-filter: blur(10px);
      border: 1px solid var(--line);
      color: var(--text-muted);
      font-size: 24px;
      opacity: 0;
      transition: opacity 0.25s var(--ease-out), background-color 0.25s var(--ease-out),
        border-color 0.25s var(--ease-out), color 0.25s var(--ease-out), box-shadow 0.25s var(--ease-out);
    }

    .nav-edge-arrow:hover {
      opacity: 1;
      background: rgba(12, 20, 51, 0.85);
      border-color: var(--cyan);
      color: var(--cyan);
      box-shadow: 0 0 16px rgba(34, 211, 238, 0.3);
    }

    .nav-edge-left {
      left: 0;
      border-radius: 0 16px 16px 0;
      border-left: none;
    }

    .nav-edge-right {
      right: 0;
      border-radius: 16px 0 0 16px;
      border-right: none;
    }

    body:hover .nav-edge-arrow {
      opacity: 0.35;
    }

    /* 全局通知系统 Toast & HUD */
    #toast-container {
      position: fixed;
      top: 72px;
      right: 28px;
      display: flex;
      flex-direction: column;
      gap: 10px;
      z-index: 120;
      pointer-events: none;
    }

    .toast-item {
      display: inline-flex;
      align-items: center;
      gap: 10px;
      max-width: 380px;
      padding: 12px 18px;
      border-radius: 12px;
      font-size: 14px;
      font-weight: 700;
      background: rgba(10, 18, 42, 0.9);
      border: 1px solid var(--line-bright);
      backdrop-filter: blur(16px);
      color: #fff;
      box-shadow: 0 10px 28px rgba(0, 0, 0, 0.5);
      pointer-events: auto;
      cursor: pointer;
      opacity: 0;
      transform: translate3d(50px, 0, 0);
      transition: transform 0.32s var(--ease-out), opacity 0.32s var(--ease-out);
      will-change: transform, opacity;
    }

    .toast-item.show {
      opacity: 1;
      transform: translate3d(0, 0, 0);
    }

    .toast-item.removing {
      opacity: 0;
      transform: translate3d(50px, 0, 0);
    }

    .toast-icon {
      font-size: 16px;
      display: grid;
      place-items: center;
    }

    /* 课堂激光笔光标 */
    #laser-pointer {
      position: fixed;
      width: 14px;
      height: 14px;
      border-radius: 50%;
      background: #ff0055;
      box-shadow: 0 0 12px #ff0055, 0 0 24px #ff0055, 0 0 40px rgba(255, 0, 85, 0.8);
      pointer-events: none;
      z-index: 200;
      transform: translate(-50%, -50%);
      display: none;
      transition: opacity 0.2s;
    }

    body.laser-active #laser-pointer {
      display: block;
    }

    body.laser-active {
      cursor: none;
    }

    /* 快捷键备忘速查面板 */
    #shortcut-sheet {
      position: fixed;
      bottom: 84px;
      left: 50%;
      transform: translateX(-50%) translateY(20px);
      background: rgba(10, 18, 42, 0.95);
      border: 1px solid var(--line-bright);
      border-radius: 16px;
      padding: 18px 24px;
      backdrop-filter: blur(20px);
      box-shadow: 0 20px 50px rgba(0, 0, 0, 0.8);
      z-index: 95;
      opacity: 0;
      pointer-events: none;
      transition: all 0.25s var(--ease-out);
    }

    #shortcut-sheet.open {
      opacity: 1;
      pointer-events: auto;
      transform: translateX(-50%) translateY(0);
    }

    .shortcut-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 16px 24px;
      font-size: 13px;
    }

    .shortcut-row {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
    }

    .kbd {
      padding: 3px 8px;
      border-radius: 6px;
      background: rgba(255, 255, 255, 0.08);
      border: 1px solid var(--line);
      font-family: monospace;
      font-size: 12px;
      color: var(--cyan);
    }

    /* 目录抽屉面板 */
    #catalog-drawer {
      position: fixed;
      inset: 0;
      z-index: 100;
      background: rgba(3, 7, 18, 0.85);
      backdrop-filter: blur(16px);
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.3s var(--ease-out);
      display: flex;
      align-items: center;
      justify-content: center;
    }

    #catalog-drawer.open {
      opacity: 1;
      pointer-events: auto;
    }

    .catalog-content {
      width: 90%;
      max-width: 900px;
      max-height: 80vh;
      overflow-y: auto;
      background: var(--bg-elevated);
      border: 1px solid var(--line-bright);
      border-radius: 24px;
      padding: 32px;
      box-shadow: 0 25px 60px rgba(0, 0, 0, 0.8);
    }

    .catalog-grid {
      display: grid;
      grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
      gap: 14px;
      margin-top: 20px;
    }

    .catalog-item {
      padding: 14px 18px;
      border-radius: 12px;
      border: 1px solid var(--line);
      background: rgba(255, 255, 255, 0.03);
      cursor: pointer;
      transition: all 0.2s;
    }

    .catalog-item:hover,
    .catalog-item.active {
      background: rgba(34, 211, 238, 0.12);
      border-color: var(--cyan);
      transform: translateX(4px);
    }

    .catalog-num {
      font-size: 12px;
      font-weight: 800;
      color: var(--cyan);
      margin-bottom: 4px;
    }

    .catalog-name {
      font-size: 14px;
      font-weight: 700;
      color: #fff;
    }

    /* 交互区：台盼蓝培养皿 (Slide 1) */
    .petri-dish {
      position: relative;
      width: 100%;
      aspect-ratio: 1;
      max-width: 440px;
      margin: 0 auto;
      border-radius: 50%;
      background: radial-gradient(circle at 40% 40%, rgba(30, 58, 138, 0.25), rgba(6, 11, 30, 0.85));
      border: 4px solid rgba(120, 200, 255, 0.3);
      box-shadow: inset 0 0 40px rgba(0, 0, 0, 0.8), 0 0 30px rgba(34, 211, 238, 0.15);
      overflow: hidden;
    }

    .petri-ripple {
      position: absolute;
      border-radius: 50%;
      pointer-events: none;
      border: 2px solid rgba(59, 130, 246, 0.8);
      transform: translate(-50%, -50%) scale(0);
      animation: rippleSpread 1.2s cubic-bezier(0.1, 0.8, 0.3, 1) forwards;
    }

    @keyframes rippleSpread {
      0% {
        transform: translate(-50%, -50%) scale(0);
        opacity: 1;
      }

      100% {
        transform: translate(-50%, -50%) scale(40);
        opacity: 0;
      }
    }

    .dish-cell {
      position: absolute;
      border-radius: 50%;
      transform: translate(-50%, -50%);
      cursor: pointer;
      transition: transform 0.3s var(--ease-spring), background-color 0.8s var(--ease-out), box-shadow 0.8s;
    }

    .dish-cell:hover {
      transform: translate(-50%, -50%) scale(1.35);
      z-index: 10;
    }

    .dish-cell.alive {
      background: radial-gradient(circle at 35% 35%, #e0f2fe, #7dd3fc 70%, #0284c7);
      box-shadow: 0 0 8px rgba(125, 211, 252, 0.5);
    }

    .dish-cell.dead {
      background: radial-gradient(circle at 35% 35%, #94a3b8, #64748b 70%, #334155);
    }

    .dish-cell.dead.stained {
      background: radial-gradient(circle at 35% 35%, #60a5fa, #1d4ed8 70%, #0f172a);
      box-shadow: 0 0 14px rgba(37, 99, 235, 0.8);
    }

    /* 交互区：微观环境与膜破坏 (Slide 2) */
    #stability-canvas {
      width: 100%;
      height: 320px;
      border-radius: 16px;
      background: rgba(3, 7, 18, 0.5);
    }

    .meter-bar {
      height: 8px;
      border-radius: 4px;
      background: rgba(255, 255, 255, 0.1);
      overflow: hidden;
      margin-top: 8px;
    }

    .meter-fill {
      height: 100%;
      width: 100%;
      background: linear-gradient(90deg, var(--green), var(--cyan));
      transition: width 0.3s;
    }

    /* 交互区：物质进出转运 (Slide 3) */
    #transport-svg {
      width: 100%;
      height: 380px;
    }

    .transport-particle {
      transition: transform 0.05s linear;
    }

    /* 交互区：信息传递三种模式 (Slide 4) */
    .tab-row {
      display: flex;
      gap: 8px;
      border-bottom: 1px solid var(--line);
      padding-bottom: 12px;
      margin-bottom: 16px;
    }

    .tab-btn {
      padding: 8px 18px;
      border-radius: 10px;
      border: 1px solid transparent;
      background: transparent;
      color: var(--text-muted);
      font-size: 14px;
      font-weight: 700;
      cursor: pointer;
      transition: all 0.2s;
    }

    .tab-btn:hover {
      color: #fff;
      background: rgba(255, 255, 255, 0.04);
    }

    .tab-btn.active {
      color: var(--cyan);
      background: rgba(34, 211, 238, 0.1);
      border-color: rgba(34, 211, 238, 0.3);
    }

    /* 交互区：磷脂自组装模拟 (Slide 8) */
    .phos-stage {
      position: relative;
      width: 100%;
      height: 260px;
      border-radius: 16px;
      overflow: hidden;
      border: 1px solid var(--line);
    }

    .phos-mol {
      position: absolute;
      left: 0;
      top: 0;
      width: 14px;
      height: 38px;
      transform-origin: 7px 7px;
      pointer-events: none;
      transition: transform 0.8s cubic-bezier(0.2, 0.9, 0.3, 1.2);
    }

    .phos-head {
      width: 14px;
      height: 14px;
      border-radius: 50%;
      background: radial-gradient(circle at 35% 35%, #f87171, #dc2626);
      box-shadow: 0 0 6px rgba(239, 68, 68, 0.5);
    }

    .phos-tail {
      position: relative;
      width: 14px;
      height: 24px;
      margin: 0 auto;
    }

    .phos-tail::before,
    .phos-tail::after {
      content: "";
      position: absolute;
      top: -2px;
      width: 2px;
      height: 26px;
      background: #fbbf24;
      border-radius: 1px;
    }

    .phos-tail::before {
      left: 4px;
    }

    .phos-tail::after {
      left: 8px;
    }

    /* 交互区：人鼠细胞融合 (Slide 10) */
    #fusion-canvas {
      width: 100%;
      height: 320px;
      border-radius: 16px;
      background: rgba(0, 0, 0, 0.3);
    }

    /* 交互区：流动镶嵌模型 (Slide 12) */
    .model-wrapper {
      position: relative;
      width: 100%;
      height: 360px;
      border-radius: 20px;
      overflow: hidden;
      border: 1px solid var(--line);
      background: radial-gradient(circle at 50% 50%, #0f1d44, #060b1e);
    }

    #mosaic-svg {
      width: 100%;
      height: 100%;
    }

    /* 膜蛋白流动漂移：只沿膜面横向往复，直观表现膜的横向流动性 */
    @keyframes mosaicDrift {

      0%,
      100% {
        transform: translateX(-7px);
      }

      50% {
        transform: translateX(7px);
      }
    }

    .mosaic-drift {
      animation: mosaicDrift 7s ease-in-out infinite;
      will-change: transform;
    }

    /* 磷脂分子沿膜面的轻微行波漂移：相邻分子相位错开，形成连续的流动感 */
    @keyframes lipidSway {

      0%,
      100% {
        transform: translateX(-3.2px) translateY(0.6px);
      }

      50% {
        transform: translateX(3.2px) translateY(-0.6px);
      }
    }

    .lipid-sway {
      animation: lipidSway 6.5s ease-in-out infinite;
      will-change: transform;
    }

    .hotspot-label {
      position: absolute;
      transform: translate(-50%, -50%);
      padding: 6px 14px;
      border-radius: 999px;
      font-size: 12px;
      font-weight: 800;
      color: #fff;
      background: rgba(6, 11, 30, 0.85);
      border: 1.5px solid var(--cyan);
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
      cursor: pointer;
      transition: all 0.25s var(--ease-spring);
    }

    .hotspot-label:hover,
    .hotspot-label.active {
      background: var(--cyan);
      color: #020617;
      transform: translate(-50%, -50%) scale(1.15);
      box-shadow: var(--shadow-glow);
    }

    /* 时间线与展开折叠 */
    .timeline-item {
      position: relative;
      padding-left: 28px;
      border-left: 2px solid var(--line);
      margin-bottom: 18px;
      transition: border-color 0.3s;
    }

    .timeline-item:hover {
      border-color: var(--cyan);
    }

    .timeline-point {
      position: absolute;
      left: -7px;
      top: 0;
      width: 12px;
      height: 12px;
      border-radius: 50%;
      background: var(--bg-deep);
      border: 2px solid var(--cyan);
      box-shadow: 0 0 8px var(--cyan);
    }

    .timeline-year {
      font-size: 13px;
      font-weight: 800;
      color: var(--amber);
      margin-bottom: 2px;
    }

    .timeline-title {
      font-size: 16px;
      font-weight: 700;
      color: #fff;
      margin-bottom: 6px;
    }

    /* 题目选项 */
    .quiz-opt {
      display: flex;
      align-items: center;
      gap: 14px;
      padding: 14px 18px;
      border-radius: 12px;
      border: 1px solid var(--line);
      background: rgba(255, 255, 255, 0.03);
      cursor: pointer;
      transition: all 0.2s;
      margin-bottom: 10px;
    }

    .quiz-opt:hover {
      background: rgba(255, 255, 255, 0.08);
      border-color: var(--line-bright);
      transform: translateX(4px);
    }

    .quiz-opt.correct {
      background: rgba(16, 185, 129, 0.15);
      border-color: var(--green);
      color: var(--green);
    }

    .quiz-opt.wrong {
      background: rgba(239, 68, 68, 0.15);
      border-color: var(--red);
      color: var(--red);
    }

    .quiz-letter {
      width: 28px;
      height: 28px;
      border-radius: 50%;
      border: 1.5px solid currentColor;
      display: grid;
      place-items: center;
      font-weight: 800;
      font-size: 13px;
      flex: 0 0 auto;
    }

    /* 判断题（点击翻看答案） */
    .tf-item {
      padding: 11px 14px;
      border-radius: 12px;
      border: 1px solid var(--line);
      background: rgba(255, 255, 255, 0.03);
      cursor: pointer;
      transition: all 0.2s;
      margin-bottom: 10px;
      font-size: 13px;
      line-height: 1.6;
      color: var(--text-muted);
    }

    .tf-item:hover {
      background: rgba(255, 255, 255, 0.07);
      border-color: var(--line-bright);
      transform: translateX(4px);
    }

    .tf-item:last-child {
      margin-bottom: 0;
    }

    .tf-answer {
      margin-top: 7px;
      font-weight: 700;
    }

    /* Slide 14 选择题排版 */
    #slide-14 .q-stem {
      font-size: 14px;
      font-weight: 700;
      color: #fff;
      margin-bottom: 10px;
      line-height: 1.6;
    }

    #slide-14 .quiz-opt {
      padding: 10px 16px;
      font-size: 13.5px;
      margin-bottom: 8px;
    }

    #slide-14 .quiz-letter {
      width: 26px;
      height: 26px;
      font-size: 12.5px;
    }

    #slide-14 .quiz-feedback {
      margin-top: 10px;
      font-size: 13px;
      line-height: 1.6;
    }

    #slide-14 .tf-item {
      font-size: 13.5px;
      padding: 12px 16px;
    }

    /* 提示浮窗与徽标 */
    .pill {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      padding: 3px 10px;
      border-radius: 6px;
      font-size: 12px;
      font-weight: 700;
    }

    .pill-cyan {
      background: rgba(34, 211, 238, 0.12);
      color: var(--cyan);
      border: 1px solid rgba(34, 211, 238, 0.25);
    }

    .pill-amber {
      background: rgba(245, 158, 11, 0.12);
      color: var(--amber);
      border: 1px solid rgba(245, 158, 11, 0.25);
    }

    .pill-green {
      background: rgba(16, 185, 129, 0.12);
      color: var(--green);
      border: 1px solid rgba(16, 185, 129, 0.25);
    }

    .pill-purple {
      background: rgba(168, 85, 247, 0.12);
      color: var(--purple);
      border: 1px solid rgba(168, 85, 247, 0.25);
    }

    /* ===================== 移动端 / 小屏适配 ===================== */
    @media (max-width: 860px) {

      /* 顶栏精简，避免文字换行挤压 */
      #top-bar {
        height: 50px;
        padding: 0 14px;
      }

      .brand {
        gap: 8px;
        font-size: 12px;
        white-space: nowrap;
      }

      .brand-badge {
        width: 7px;
        height: 7px;
      }

      .chapter-tag {
        display: none;
      }

      .unit-info {
        max-width: 46vw;
        padding: 3px 12px;
        font-size: 11.5px;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
      }

      /* 幻灯片留白与滚动安全区 */
      .slide {
        padding: 64px 16px 116px;
      }

      .container {
        justify-content: flex-start;
      }

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

      .slide-desc {
        font-size: 14px;
      }

      .card {
        padding: 16px;
        border-radius: 16px;
      }

      .card-title {
        font-size: 16px;
      }

      /* 底部导航紧凑贴底 */
      #dock {
        bottom: 12px;
        gap: 2px;
        padding: 5px 8px;
        border-radius: 14px;
      }

      .dock-btn {
        width: 34px;
        height: 34px;
        border-radius: 10px;
      }

      .dock-btn svg {
        width: 18px;
        height: 18px;
      }

      #page-indicator {
        padding: 5px 9px;
        font-size: 12px;
      }

      /* 交互画布 / 模型：收敛高度；横纵比明确的 SVG 交给比例自适应 */
      #transport-svg {
        height: auto;
        aspect-ratio: 500 / 380;
      }

      #stability-canvas,
      #fusion-canvas {
        height: 240px;
      }

      .model-wrapper {
        height: 200px;
      }

      .phos-stage {
        height: 220px;
      }

      #phos-interactive-wrap {
        height: 240px !important;
      }

      /* 流动镶嵌模型标签：小屏单行不换行、缩小并内收，避免竖排换行与出界 */
      #slide-12 .hotspot-label {
        white-space: nowrap;
        font-size: 11px;
        padding: 5px 10px;
      }

      #slide-12 [style*="left: 82%"] {
        left: 76% !important;
      }

      #slide-12 [style*="left: 90%"] {
        left: 84% !important;
      }

      /* 信息交流页：标签栏与内容区改为单列堆叠 */
      .tab-row {
        flex-direction: column;
        gap: 6px;
        padding-bottom: 10px;
      }

      .tab-btn {
        width: 100%;
        text-align: left;
        padding: 10px 14px;
        font-size: 13px;
        line-height: 1.4;
      }

      #slide-4 .card {
        min-height: auto !important;
      }

      #slide-4 [style*="grid-template-columns"] {
        grid-template-columns: 1fr !important;
        gap: 14px !important;
      }

      #comm-visual-box {
        height: 220px !important;
      }

      /* 思维导图：保持可读尺寸，允许横向滚动 */
      #slide-13 .card {
        overflow-x: auto;
        overflow-y: hidden;
        padding: 12px;
      }

      #mindmap-svg {
        min-width: 700px;
        height: 360px;
      }

      /* 浮层适配 */
      #toast-container {
        top: 58px;
        right: 12px;
        left: 12px;
      }

      .toast-item {
        max-width: none;
      }

      #shortcut-sheet {
        width: 92vw;
        max-width: 480px;
        padding: 16px;
      }

      .shortcut-grid {
        grid-template-columns: 1fr 1fr;
        gap: 12px 18px;
      }

      .catalog-content {
        padding: 22px;
        max-height: 84vh;
      }

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

      /* 小屏无鼠标，隐藏激光笔按钮，简化底栏 */
      #btn-laser {
        display: none;
      }
    }

    @media (max-width: 520px) {

      #slide-0 .slide-title {
        font-size: clamp(28px, 8.6vw, 42px) !important;
      }

      .slide-title {
        font-size: clamp(20px, 6.4vw, 28px);
      }

      #dock {
        bottom: 10px;
      }

      .dock-btn {
        width: 32px;
        height: 32px;
      }

      .grid-2,
      .grid-3 {
        gap: 14px;
      }

      /* 底部操作按钮更利于触控 */
      .btn {
        padding: 9px 14px;
        font-size: 13px;
      }

      #page-indicator {
        padding: 5px 7px;
      }
    }