/* ==========================================
           Vibe Coding — 专有样式
           宽度继承全局 85%，风格延续 part4 的温暖杂志风
           ========================================== */

        /* ---- 章节二级标题变体 ---- */
        .chapter-section h3 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.2rem;
            font-weight: 600;
            color: var(--primary-dark);
            margin: var(--space-lg) 0 var(--space-md);
            padding-left: var(--space-md);
            border-left: 3px solid var(--primary);
        }

        .chapter-section h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.05rem;
            font-weight: 600;
            color: var(--text-primary);
            margin: var(--space-md) 0 var(--space-sm);
        }

        /* ---- 定义卡 ---- */
        .def-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .def-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            text-align: center;
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
            position: relative;
            overflow: hidden;
        }

        .def-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 3px;
            transition: opacity var(--transition-base);
        }

        .def-card:nth-child(1)::before {
            background: linear-gradient(90deg, #EC4899, #F472B6);
        }

        .def-card:nth-child(2)::before {
            background: linear-gradient(90deg, #3B82F6, #60A5FA);
        }

        .def-card:nth-child(3)::before {
            background: linear-gradient(90deg, #10B981, #34D399);
        }

        .def-card:nth-child(4)::before {
            background: linear-gradient(90deg, #F59E0B, #FBBF24);
        }

        .def-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .def-card:hover::before {
            opacity: 1;
        }

        .def-card:nth-child(1):hover { border-color: rgba(236, 72, 153, 0.3); }
        .def-card:nth-child(2):hover { border-color: rgba(59, 130, 246, 0.3); }
        .def-card:nth-child(3):hover { border-color: rgba(16, 185, 129, 0.3); }
        .def-card:nth-child(4):hover { border-color: rgba(245, 158, 11, 0.3); }

        .def-label {
            display: inline-block;
            font-size: 0.65rem;
            letter-spacing: 0.1em;
            padding: 3px 12px;
            border-radius: var(--radius-xl);
            margin-bottom: var(--space-sm);
        }

        .def-card h3 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.15rem;
            color: var(--text-primary);
            margin-bottom: 2px;
        }

        .def-en {
            font-size: 0.7rem;
            color: var(--text-muted);
            letter-spacing: 0.05em;
            margin-bottom: var(--space-sm);
        }

        .def-body {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
            text-align: left;
        }

        .def-body strong {
            color: var(--primary);
        }

        /* ---- 核心要素卡片 ---- */
        .element-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .element-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            text-align: center;
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
        }

        .element-card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-hover);
        }

        .element-card:nth-child(1) { border-top: 3px solid #F59E0B; }
        .element-card:nth-child(2) { border-top: 3px solid #3B82F6; }
        .element-card:nth-child(3) { border-top: 3px solid #10B981; }

        .element-card:hover { border-color: rgba(245, 158, 11, 0.3); }

        .element-icon {
            width: 56px;
            height: 56px;
            margin: 0 auto var(--space-md);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.5rem;
        }

        .element-card:nth-child(1) .element-icon { background: #FFFBEB; border: 1px solid #FDE68A; }
        .element-card:nth-child(2) .element-icon { background: #EFF6FF; border: 1px solid #BFDBFE; }
        .element-card:nth-child(3) .element-icon { background: #ECFDF5; border: 1px solid #A7F3D0; }

        .element-card h3 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.1rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .element-body {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        /* ---- 工具卡片 ---- */
        .tool-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .tool-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
            position: relative;
        }

        .tool-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .tool-card:nth-child(1) { border-top: 3px solid #6366F1; }
        .tool-card:nth-child(2) { border-top: 3px solid #F59E0B; }
        .tool-card:nth-child(3) { border-top: 3px solid #EC4899; }
        .tool-card:nth-child(4) { border-top: 3px solid #10B981; }
        .tool-card:nth-child(5) { border-top: 3px solid #8B5CF6; }
        .tool-card:nth-child(6) { border-top: 3px solid #EF4444; }
        .tool-card:nth-child(7) { border-top: 3px solid #0EA5E9; }

        .tool-card:nth-child(1):hover { border-color: rgba(99, 102, 241, 0.3); }
        .tool-card:nth-child(2):hover { border-color: rgba(245, 158, 11, 0.3); }
        .tool-card:nth-child(3):hover { border-color: rgba(236, 72, 153, 0.3); }
        .tool-card:nth-child(4):hover { border-color: rgba(16, 185, 129, 0.3); }
        .tool-card:nth-child(5):hover { border-color: rgba(139, 92, 246, 0.3); }
        .tool-card:nth-child(6):hover { border-color: rgba(239, 68, 68, 0.3); }
        .tool-card:nth-child(7):hover { border-color: rgba(14, 165, 233, 0.3); }

        .tool-card h3 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.1rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .tool-badge {
            display: inline-block;
            font-size: 0.6rem;
            padding: 2px 8px;
            border-radius: var(--radius-sm);
            font-weight: 600;
            margin-left: var(--space-xs);
            vertical-align: middle;
        }

        .tool-badge.popular {
            background: #FDF2F8;
            color: #BE185D;
            border: 1px solid #FBCFE8;
        }

        .tool-badge.new {
            background: #ECFDF5;
            color: #047857;
            border: 1px solid #A7F3D0;
        }

        .tool-badge.opensource {
            background: #EFF6FF;
            color: #1E40AF;
            border: 1px solid #BFDBFE;
        }

        .tool-badge.domestic {
            background: #FEF2F2;
            color: #B91C1C;
            border: 1px solid #FECACA;
        }

        .tool-desc {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        .tool-features {
            list-style: none;
            padding: 0;
            margin-top: var(--space-sm);
        }

        .tool-features li {
            font-size: 0.8rem;
            color: var(--text-secondary);
            padding: 2px 0;
            padding-left: 16px;
            position: relative;
        }

        .tool-features li::before {
            content: '✦';
            position: absolute;
            left: 0;
            color: var(--primary);
            font-size: 0.6rem;
            top: 4px;
        }

        /* ---- 工作流步骤 ---- */
        .flow-steps {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-md);
            justify-content: center;
            margin-bottom: var(--space-lg);
        }

        .flow-step {
            flex: 1;
            min-width: 160px;
            max-width: 220px;
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-md);
            padding: var(--space-lg) var(--space-md);
            text-align: center;
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
            position: relative;
        }

        .flow-step:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-hover);
        }

        .flow-step:not(:last-child)::after {
            content: '→';
            position: absolute;
            right: -18px;
            top: 50%;
            transform: translateY(-50%);
            font-size: 1.2rem;
            color: var(--primary);
            font-weight: bold;
        }

        .flow-num {
            display: inline-block;
            width: 28px;
            height: 28px;
            line-height: 28px;
            border-radius: 50%;
            background: linear-gradient(135deg, var(--primary), var(--primary-dark));
            color: #fff;
            font-size: 0.8rem;
            font-weight: 600;
            margin-bottom: var(--space-sm);
        }

        .flow-step h4 {
            font-size: 0.9rem;
            color: var(--text-primary);
            margin-bottom: var(--space-xs);
        }

        .flow-step p {
            font-size: 0.75rem;
            color: var(--text-secondary);
            line-height: 1.5;
        }

        /* ---- 场景卡片 ---- */
        .scene-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .scene-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            text-align: center;
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
        }

        .scene-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
            border-color: var(--border-accent);
        }

        .scene-icon {
            font-size: 2rem;
            margin-bottom: var(--space-sm);
        }

        .scene-card h3 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .scene-desc {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.6;
        }

        /* ---- 技术卡片 ---- */
        .tech-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .tech-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
            position: relative;
        }

        .tech-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .tech-card:nth-child(1) { border-top: 3px solid #6366F1; }
        .tech-card:nth-child(2) { border-top: 3px solid #F59E0B; }
        .tech-card:nth-child(3) { border-top: 3px solid #EC4899; }
        .tech-card:nth-child(4) { border-top: 3px solid #10B981; }

        .tech-card:hover { border-color: var(--border-accent); }

        .tech-card h3 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.1rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .tech-desc {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        /* ---- 编程范式对比 ---- */
        .paradigm-comparison {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        @media (max-width: 900px) {
            .paradigm-comparison {
                grid-template-columns: 1fr;
            }
            .flow-step:not(:last-child)::after {
                display: none;
            }
        }

        .paradigm-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
            text-align: center;
        }

        .paradigm-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .paradigm-card.traditional { border-top: 3px solid #94A3B8; }
        .paradigm-card.copilot { border-top: 3px solid #3B82F6; }
        .paradigm-card.vibe { border-top: 3px solid #10B981; }

        .paradigm-card h3 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.05rem;
            color: var(--text-primary);
            margin-bottom: var(--space-xs);
        }

        .paradigm-era {
            font-size: 0.7rem;
            color: var(--text-muted);
            margin-bottom: var(--space-sm);
        }

        .paradigm-body {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
            text-align: left;
        }

        .paradigm-body ul {
            list-style: none;
            padding: 0;
            margin-top: var(--space-sm);
        }

        .paradigm-body ul li {
            padding: 3px 0;
            font-size: 0.8rem;
            color: var(--text-secondary);
            padding-left: 16px;
            position: relative;
        }

        .paradigm-body ul li::before {
            content: '▸';
            position: absolute;
            left: 0;
            color: var(--primary);
        }

        /* ---- 两栏布局 ---- */
        .two-col {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        @media (max-width: 768px) {
            .two-col {
                grid-template-columns: 1fr;
            }
        }

        /* ---- 子主题列表 ---- */
        .topic-list {
            list-style: none;
            padding: 0;
        }

        .topic-list li {
            padding: var(--space-sm) var(--space-md);
            margin-bottom: var(--space-xs);
            background: var(--bg-elevated);
            border-radius: var(--radius-sm);
            border-left: 3px solid var(--accent);
            color: var(--text-secondary);
            font-size: 0.85rem;
            transition: all var(--transition-base);
        }

        .topic-list li:hover {
            border-left-color: var(--primary);
            transform: translateX(4px);
        }

        .topic-list li strong {
            color: var(--text-primary);
        }

        /* ---- 名词定义区块 ---- */
        .term-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: var(--space-md);
            margin-bottom: var(--space-lg);
        }

        .term-item {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-md);
            padding: var(--space-md) var(--space-lg);
            transition: all var(--transition-base);
            box-shadow: var(--shadow-sm);
        }

        .term-item:hover {
            border-color: var(--border-accent);
            transform: translateX(4px);
            box-shadow: var(--shadow-hover);
        }

        .term-word {
            font-weight: 600;
            color: var(--primary-dark);
            font-size: 0.9rem;
        }

        .term-def {
            color: var(--text-secondary);
            font-size: 0.8rem;
            margin-top: 2px;
            line-height: 1.6;
        }

        /* ---- 代码示例块 ---- */
        .code-example {
            background: #1E1E2E;
            border: 1px solid #313148;
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            margin-bottom: var(--space-lg);
            overflow-x: auto;
        }

        .code-example-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: var(--space-sm);
            padding-bottom: var(--space-sm);
            border-bottom: 1px solid #313148;
        }

        .code-example-title {
            font-family: 'Noto Sans SC', sans-serif;
            font-size: 0.75rem;
            color: #A6ACCD;
            letter-spacing: 0.05em;
        }

        .code-example-prompt {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.8rem;
            color: #A6E3A1;
            line-height: 1.7;
        }

        .code-example-prompt .comment {
            color: #6C7086;
        }

        .code-example-prompt .keyword {
            color: #CB76FF;
        }

        .code-example-prompt .string {
            color: #A6E3A1;
        }

        .code-example-prompt .func {
            color: #89B4FA;
        }

        /* ---- 评估方法卡片 ---- */
        .eval-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .eval-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
            border-top: 3px solid var(--primary);
        }

        .eval-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .eval-card:nth-child(1) { border-top-color: #6366F1; }
        .eval-card:nth-child(2) { border-top-color: #F59E0B; }
        .eval-card:nth-child(3) { border-top-color: #10B981; }

        .eval-card h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.05rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .eval-card p {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        /* ---- 算法分类大卡片 ---- */
        .algo-section-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            margin-bottom: var(--space-md);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
        }

        .algo-section-card:hover {
            border-color: var(--border-accent);
            box-shadow: var(--shadow-hover);
        }

        .algo-section-card h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.05rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
            display: flex;
            align-items: center;
            gap: var(--space-sm);
        }

        .algo-section-card p {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        /* ---- 论点卡片 ---- */
        .arguments-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .argument-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            display: flex;
            gap: var(--space-md);
            align-items: flex-start;
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
        }

        .argument-card:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-hover);
        }

        .arg-icon {
            width: 48px;
            height: 48px;
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.3rem;
            flex-shrink: 0;
            border: 1px solid;
        }

        .argument-card h3 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1rem;
            color: var(--text-primary);
            margin-bottom: 4px;
        }

        .argument-card p {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        /* ---- 总结框 ---- */
        .summary-box {
            background: linear-gradient(135deg, hsl(var(--primary-hue) 60% 96%), hsl(var(--primary-hue) 40% 94%));
            border: 1px solid var(--border-accent);
            border-radius: var(--radius-lg);
            padding: var(--space-lg) var(--space-xl);
            margin-bottom: var(--space-lg);
        }

        .summary-box p {
            color: var(--text-secondary);
            font-size: 0.9rem;
            line-height: 1.7;
        }

        /* ---- 收敛框 ---- */
        .convergence-box {
            background: var(--bg-elevated);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg) var(--space-xl);
            margin-bottom: var(--space-lg);
        }

        .convergence-box p {
            color: var(--text-secondary);
            font-size: 0.95rem;
            line-height: 1.7;
        }

        /* ---- 结论框 ---- */
        .conclusion-box {
            background: linear-gradient(135deg, hsl(var(--primary-hue) 50% 95%), hsl(var(--primary-hue) 30% 92%));
            border: 2px solid var(--primary);
            border-radius: var(--radius-lg);
            padding: var(--space-lg) var(--space-xl);
            margin-bottom: var(--space-lg);
        }

        .conclusion-box p {
            color: var(--text-secondary);
            font-size: 0.9rem;
            line-height: 1.7;
        }

        /* ---- 过渡块 ---- */
        .transition-block {
            background: linear-gradient(135deg, hsl(var(--primary-hue) 60% 96%), hsl(var(--primary-hue) 40% 94%));
            border-left: 4px solid var(--primary);
            border-radius: 0 var(--radius-lg) var(--radius-lg) 0;
            padding: var(--space-lg) var(--space-xl);
            text-align: center;
        }

        .transition-block p {
            color: var(--text-primary);
            font-size: 1.05rem;
            line-height: 1.8;
            font-family: 'Noto Serif SC', serif;
        }

        /* ---- 双极观点对比 ---- */
        .debate-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        @media (max-width: 768px) {
            .debate-grid {
                grid-template-columns: 1fr;
            }
        }

        .debate-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
        }

        .debate-card:hover {
            box-shadow: var(--shadow-hover);
        }

        .debate-card.for {
            border-top: 3px solid #10B981;
        }

        .debate-card.against {
            border-top: 3px solid #EF4444;
        }

        .debate-card h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1rem;
            margin-bottom: var(--space-sm);
            display: flex;
            align-items: center;
            gap: var(--space-xs);
        }

        .debate-card.for h4 { color: #047857; }
        .debate-card.against h4 { color: #B91C1C; }

        .debate-card p, .debate-card li {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        .debate-card ul {
            list-style: none;
            padding: 0;
            margin-top: var(--space-sm);
        }

        .debate-card ul li {
            padding: 3px 0;
            padding-left: 16px;
            position: relative;
        }

        .debate-card ul li::before {
            content: '▸';
            position: absolute;
            left: 0;
        }

        .debate-card.for ul li::before { color: #10B981; }
        .debate-card.against ul li::before { color: #EF4444; }

        /* ---- 路线图 ---- */
        .roadmap {
            position: relative;
            padding-left: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .roadmap::before {
            content: '';
            position: absolute;
            left: 8px;
            top: 0;
            bottom: 0;
            width: 2px;
            background: linear-gradient(to bottom, var(--primary), var(--accent));
        }

        .roadmap-item {
            position: relative;
            margin-bottom: var(--space-lg);
            padding-left: var(--space-md);
        }

        .roadmap-item::before {
            content: '';
            position: absolute;
            left: calc(-1 * var(--space-lg) + 4px);
            top: 6px;
            width: 10px;
            height: 10px;
            border-radius: 50%;
            background: var(--primary);
            border: 2px solid var(--bg-primary);
        }

        .roadmap-item h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1rem;
            color: var(--text-primary);
            margin-bottom: var(--space-xs);
        }

        .roadmap-item p {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        .roadmap-item .time-tag {
            display: inline-block;
            font-size: 0.65rem;
            padding: 2px 8px;
            border-radius: var(--radius-sm);
            background: hsl(var(--primary-hue) 60% 96%);
            color: var(--primary-dark);
            font-weight: 600;
            margin-bottom: var(--space-xs);
        }

        /* ==========================================
           新增：可视化容器
           ========================================== */
        .viz-section {
            margin: var(--space-2xl) 0;
        }

        .viz-title {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.3rem;
            font-weight: 700;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
            text-align: center;
        }

        .viz-subtitle {
            color: var(--text-secondary);
            font-size: 0.95rem;
            line-height: 1.8;
            margin-bottom: var(--space-lg);
            text-align: center;
            max-width: 700px;
            margin-left: auto;
            margin-right: auto;
        }

        .viz-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-xl) var(--space-lg);
            margin-bottom: var(--space-2xl);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
            position: relative;
            overflow: hidden;
        }

        .viz-card:hover {
            border-color: var(--border-accent);
            box-shadow: var(--shadow-hover);
        }

        .viz-card h3 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.15rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
            display: flex;
            align-items: center;
            gap: var(--space-sm);
        }

        .viz-card p {
            color: var(--text-secondary);
            font-size: 0.9rem;
            line-height: 1.7;
            margin-bottom: var(--space-md);
        }

        .viz-svg-container {
            background: linear-gradient(135deg, #FAFBFC, #F8FAFC);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            margin: var(--space-lg) 0;
            text-align: center;
            overflow: hidden;
        }

        .viz-svg-container svg {
            display: block;
            width: 100%;
            height: auto;
            max-width: 700px;
            margin: 0 auto;
        }

        .viz-caption {
            font-size: 0.8rem;
            color: var(--text-muted);
            text-align: center;
            margin-top: var(--space-sm);
            font-style: italic;
        }

        /* ==========================================
           布局与阅读体验增强
           ========================================== */
        .article-subtitle {
            color: var(--text-secondary);
            font-size: 1rem;
            margin-top: var(--space-xs);
            margin-bottom: var(--space-md);
            letter-spacing: 0.02em;
        }

        .lead-paragraph {
            color: var(--text-primary);
            font-size: 1.08rem;
            line-height: 1.85;
            margin-bottom: var(--space-lg);
        }

        .lead-paragraph strong {
            color: var(--primary-dark);
        }

        .part-intro {
            color: var(--text-secondary);
            font-size: 0.98rem;
            line-height: 1.8;
            margin-bottom: var(--space-lg);
            padding: var(--space-md) var(--space-lg);
            background: var(--bg-elevated);
            border-left: 3px solid var(--accent);
            border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
        }

        /* ---- 引子锚点卡 ---- */
        .hero-stats {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: var(--space-md);
            margin-bottom: var(--space-lg);
        }

        .stat-pill {
            display: flex;
            align-items: center;
            gap: var(--space-md);
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-left: 3px solid var(--primary);
            border-radius: var(--radius-md);
            padding: var(--space-md) var(--space-lg);
            box-shadow: var(--shadow-sm);
            transition: all var(--transition-base);
        }

        .stat-pill:nth-child(2) { border-left-color: var(--accent); }
        .stat-pill:nth-child(3) { border-left-color: #10B981; }

        .stat-pill:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-hover);
        }

        .stat-icon {
            flex-shrink: 0;
            width: 44px;
            height: 44px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.4rem;
            background: hsl(var(--primary-hue) 60% 96%);
            border-radius: var(--radius-sm);
        }

        .stat-pill:nth-child(2) .stat-icon { background: hsl(var(--accent-hue) 80% 95%); }
        .stat-pill:nth-child(3) .stat-icon { background: #ECFDF5; }

        .stat-text {
            display: flex;
            flex-direction: column;
        }

        .stat-text strong {
            font-family: 'Noto Serif SC', serif;
            font-size: 0.95rem;
            color: var(--text-primary);
        }

        .stat-text span {
            color: var(--text-secondary);
            font-size: 0.8rem;
            line-height: 1.5;
            margin-top: 2px;
        }

        /* ==========================================
           新手快速上手路径
           ========================================== */
        .quickstart-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .quickstart-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-top: 3px solid var(--primary);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            box-shadow: var(--shadow-sm);
            transition: all var(--transition-slow);
        }

        .quickstart-card:nth-child(2) { border-top-color: var(--accent); }
        .quickstart-card:nth-child(3) { border-top-color: #8B5CF6; }

        .quickstart-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .qs-head {
            display: flex;
            gap: var(--space-md);
            align-items: flex-start;
            margin-bottom: var(--space-md);
            padding-bottom: var(--space-md);
            border-bottom: 1px solid var(--border-subtle);
        }

        .qs-role-icon {
            flex-shrink: 0;
            font-size: 1.8rem;
            line-height: 1;
        }

        .qs-role {
            font-family: 'Noto Serif SC', serif;
            font-size: 1rem;
            font-weight: 600;
            color: var(--text-primary);
        }

        .qs-tag {
            font-size: 0.75rem;
            color: var(--text-muted);
            margin-top: 2px;
        }

        .qs-steps {
            list-style: none;
            padding: 0;
            margin: 0;
            counter-reset: qs;
        }

        .qs-steps li {
            position: relative;
            padding: var(--space-xs) 0 var(--space-xs) 1.9rem;
            font-size: 0.85rem;
            line-height: 1.65;
            color: var(--text-secondary);
            counter-increment: qs;
        }

        .qs-steps li::before {
            content: counter(qs);
            position: absolute;
            left: 0;
            top: 6px;
            width: 18px;
            height: 18px;
            line-height: 18px;
            text-align: center;
            font-size: 0.65rem;
            font-weight: 600;
            border-radius: 50%;
            background: hsl(var(--primary-hue) 60% 95%);
            color: var(--primary-dark);
            font-family: 'JetBrains Mono', monospace;
        }

        .qs-steps li strong { color: var(--text-primary); }

        .qs-steps li em {
            font-style: normal;
            color: var(--primary);
            font-weight: 500;
        }

        .qs-steps code {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.78rem;
            background: var(--bg-elevated);
            padding: 1px 5px;
            border-radius: 4px;
            color: var(--primary-dark);
        }

        /* ==========================================
           完整实战案例流
           ========================================== */
        .case-flow {
            margin-bottom: var(--space-lg);
        }

        .case-step {
            display: flex;
            gap: var(--space-md);
            margin-bottom: var(--space-md);
            align-items: flex-start;
        }

        .case-num {
            flex-shrink: 0;
            width: 36px;
            height: 36px;
            border-radius: 50%;
            background: linear-gradient(135deg, var(--primary), var(--primary-dark));
            color: #fff;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 600;
            font-size: 0.9rem;
            font-family: 'JetBrains Mono', monospace;
            box-shadow: var(--shadow-sm);
        }

        .case-body {
            flex: 1;
            min-width: 0;
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-md);
            padding: var(--space-md) var(--space-lg);
            box-shadow: var(--shadow-sm);
            transition: all var(--transition-base);
        }

        .case-body:hover {
            box-shadow: var(--shadow-hover);
            border-color: var(--border-accent);
        }

        .case-title {
            font-family: 'Noto Serif SC', serif;
            font-size: 0.95rem;
            font-weight: 600;
            color: var(--text-primary);
            margin-bottom: var(--space-xs);
        }

        .case-text {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.7;
        }

        .case-text strong { color: var(--primary); }

        /* ==========================================
           避坑清单
           ========================================== */
        .pitfall-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .pitfall-card {
            position: relative;
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            box-shadow: var(--shadow-sm);
            transition: all var(--transition-slow);
            overflow: hidden;
        }

        .pitfall-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 3px;
            background: linear-gradient(90deg, #EF4444, #F59E0B);
        }

        .pitfall-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .pitfall-num {
            position: absolute;
            top: var(--space-md);
            right: var(--space-lg);
            font-family: 'JetBrains Mono', monospace;
            font-size: 1.5rem;
            font-weight: 700;
            line-height: 1;
            color: var(--border-medium);
        }

        .pitfall-card h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
            margin-right: 2.5rem;
        }

        .pitfall-wrong,
        .pitfall-right {
            font-size: 0.82rem;
            line-height: 1.6;
            color: var(--text-secondary);
            margin-top: var(--space-xs);
        }

        .pitfall-wrong span,
        .pitfall-right span {
            display: inline-block;
            font-size: 0.65rem;
            font-weight: 600;
            padding: 2px 8px;
            border-radius: var(--radius-sm);
            margin-right: var(--space-xs);
            vertical-align: middle;
        }

        .pitfall-wrong span {
            background: #FEF2F2;
            color: #B91C1C;
        }

        .pitfall-right span {
            background: #ECFDF5;
            color: #047857;
        }

        /* ==========================================
           学习资源卡
           ========================================== */
        .resource-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .resource-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-md);
            padding: var(--space-lg);
            text-align: center;
            box-shadow: var(--shadow-sm);
            transition: all var(--transition-slow);
        }

        .resource-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
            border-color: var(--border-accent);
        }

        .resource-icon {
            font-size: 1.8rem;
            margin-bottom: var(--space-sm);
        }

        .resource-card h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 0.95rem;
            color: var(--text-primary);
            margin-bottom: var(--space-xs);
        }

        .resource-card p {
            color: var(--text-secondary);
            font-size: 0.82rem;
            line-height: 1.6;
        }

        /* ==========================================
           AI 边界：能力雷达图
           ========================================== */
        .radar-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
            align-items: center;
        }

        @media (max-width: 768px) {
            .radar-grid {
                grid-template-columns: 1fr;
            }
        }

        .boundary-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .boundary-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
        }

        .boundary-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .boundary-card.can { border-top: 3px solid #10B981; }
        .boundary-card.cant { border-top: 3px solid #EF4444; }
        .boundary-card.maybe { border-top: 3px solid #F59E0B; }

        .boundary-card h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .boundary-card p, .boundary-card li {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        .boundary-card ul {
            list-style: none;
            padding: 0;
            margin-top: var(--space-sm);
        }

        .boundary-card ul li {
            padding: 3px 0;
            padding-left: 16px;
            position: relative;
        }

        .boundary-card ul li::before {
            content: '▸';
            position: absolute;
            left: 0;
        }

        .boundary-card.can ul li::before { color: #10B981; }
        .boundary-card.cant ul li::before { color: #EF4444; }
        .boundary-card.maybe ul li::before { color: #F59E0B; }

        /* ==========================================
           移动端横向目录条（默认显示，大屏隐藏）
           ========================================== */
        .toc-bar {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-xs);
            padding: var(--space-sm) 0 var(--space-md);
            margin-bottom: var(--space-md);
            border-bottom: 1px dashed var(--border-medium);
        }

        .toc-bar a {
            font-size: 0.78rem;
            color: var(--text-secondary);
            text-decoration: none;
            padding: 4px 12px;
            border-radius: var(--radius-xl);
            background: var(--bg-elevated);
            border: 1px solid var(--border-subtle);
            transition: all var(--transition-base);
        }

        .toc-bar a:hover {
            color: var(--primary);
            border-color: var(--primary);
        }

        @media (min-width: 1240px) {
            .toc-bar {
                display: none;
            }
        }

        /* ==========================================
           响应式：移动端案例流与卡片的微调
           ========================================== */
        @media (max-width: 768px) {
            .case-step {
                gap: var(--space-sm);
            }

            .case-num {
                width: 30px;
                height: 30px;
                font-size: 0.8rem;
            }

            .case-body {
                padding: var(--space-md);
            }

            .pitfall-num {
                font-size: 1.2rem;
            }

            .stat-pill {
                padding: var(--space-md);
            }
        }

        /* ==========================================
           共享组件：与 part4 对齐
           ========================================== */

        /* ---- 信息卡片 ---- */
        .info-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            margin-bottom: var(--space-lg);
            box-shadow: var(--shadow-sm);
            transition: all var(--transition-slow);
        }

        .info-card:hover {
            border-color: var(--border-accent);
            box-shadow: var(--shadow-hover);
        }

        .info-card h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.05rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        /* ---- 公式块 ---- */
        .formula-box {
            background: hsl(var(--primary-hue) 40% 97%);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-md);
            padding: var(--space-sm) var(--space-md);
            margin-bottom: var(--space-md);
            font-size: 0.95rem;
            line-height: 2;
            overflow-x: auto;
            text-align: center;
        }

        .formula-box mjx-container {
            display: inline-block;
            vertical-align: middle;
        }

        .formula-box mjx-container[display="true"] {
            display: block;
            margin: var(--space-xs) 0;
        }

        .formula-desc {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
            margin-top: var(--space-xs);
            font-family: 'Noto Sans SC', sans-serif;
        }

        /* ---- 注意力卡片 ---- */
        .attention-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .attention-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            text-align: center;
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
            border-top: 3px solid #6366F1;
        }

        .attention-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .attention-card:nth-child(2) { border-top-color: #F59E0B; }
        .attention-card:nth-child(3) { border-top-color: #10B981; }
        .attention-card:nth-child(4) { border-top-color: #EC4899; }

        .attention-card h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .attention-card p {
            color: var(--text-secondary);
            font-size: 0.83rem;
            line-height: 1.6;
        }

        .attention-card .mono {
            font-family: 'JetBrains Mono', monospace;
            font-size: 0.8rem;
            color: var(--primary);
            background: hsl(var(--primary-hue) 60% 96%);
            padding: 2px 8px;
            border-radius: var(--radius-sm);
            display: inline-block;
            margin: var(--space-xs) 0;
        }

        /* ---- 训练阶段时间线 ---- */
        .stage-timeline {
            position: relative;
            padding-left: 2rem;
            margin-bottom: var(--space-lg);
        }

        .stage-timeline::before {
            content: '';
            position: absolute;
            left: 0.6rem;
            top: 0;
            bottom: 0;
            width: 2px;
            background: linear-gradient(to bottom, var(--primary), var(--accent));
        }

        .stage-item {
            position: relative;
            margin-bottom: var(--space-lg);
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
        }

        .stage-item:hover {
            border-color: var(--border-accent);
            box-shadow: var(--shadow-hover);
        }

        .stage-item::before {
            content: '';
            position: absolute;
            left: -1.7rem;
            top: 1.2rem;
            width: 12px;
            height: 12px;
            border-radius: 50%;
            background: var(--primary);
            border: 2px solid var(--bg-canvas);
        }

        .stage-item:nth-child(2)::before { background: #F59E0B; }
        .stage-item:nth-child(3)::before { background: #10B981; }
        .stage-item:nth-child(4)::before { background: #6366F1; }
        .stage-item:nth-child(5)::before { background: #8B5CF6; }

        .stage-item h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1.05rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .stage-item p {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }

        .stage-badge {
            display: inline-block;
            font-size: 0.65rem;
            padding: 2px 10px;
            border-radius: var(--radius-xl);
            margin-left: var(--space-sm);
            vertical-align: middle;
        }

        /* ---- 推理流程 ---- */
        .inference-flow {
            display: flex;
            flex-wrap: wrap;
            gap: var(--space-sm);
            justify-content: center;
            margin-bottom: var(--space-lg);
        }

        .inference-step {
            flex: 1;
            min-width: 140px;
            max-width: 180px;
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-md);
            text-align: center;
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
        }

        .inference-step:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-hover);
        }

        .inference-num {
            display: inline-block;
            width: 26px;
            height: 26px;
            line-height: 26px;
            border-radius: 50%;
            background: linear-gradient(135deg, var(--primary), var(--accent));
            color: #fff;
            font-size: 0.75rem;
            font-weight: 600;
            margin-bottom: var(--space-xs);
        }

        .inference-step h4 {
            font-size: 0.85rem;
            color: var(--text-primary);
            margin-bottom: var(--space-xs);
        }

        .inference-step p {
            font-size: 0.72rem;
            color: var(--text-secondary);
            line-height: 1.5;
        }

        /* ==========================================
           动画关键帧（与 part4 对齐）
           ========================================== */
        @keyframes forwardSignal {
            0% { opacity: 0; stroke-dashoffset: 300; }
            15% { opacity: 1; }
            85% { opacity: 1; }
            100% { opacity: 0; stroke-dashoffset: 0; }
        }

        .forward-signal {
            animation: forwardSignal 2.5s ease-in-out infinite;
        }

        @keyframes backwardSignal {
            0% { opacity: 0; stroke-dashoffset: 300; }
            15% { opacity: 1; }
            85% { opacity: 1; }
            100% { opacity: 0; stroke-dashoffset: 0; }
        }

        .backward-signal {
            animation: backwardSignal 2.5s ease-in-out infinite reverse;
        }

        @keyframes nodeGlow {
            0%, 100% { r: 10; opacity: 0.8; }
            50% { r: 13; opacity: 1; }
        }

        .node-glow {
            animation: nodeGlow 2s ease-in-out infinite;
        }

        @keyframes lossDrop {
            0% { stroke-dashoffset: 600; }
            100% { stroke-dashoffset: 0; }
        }

        .loss-curve {
            animation: lossDrop 4s ease-out infinite;
        }

        @keyframes ballRoll {
            0% { transform: translate(80px, 30px); }
            30% { transform: translate(200px, 90px); }
            60% { transform: translate(320px, 50px); }
            100% { transform: translate(420px, 130px); }
        }

        .loss-ball {
            animation: ballRoll 4s ease-out infinite;
        }

        @keyframes convSlide {
            0%, 100% { opacity: 0.6; }
            50% { opacity: 1; }
        }

        .conv-kernel {
            animation: convSlide 1.5s ease-in-out infinite;
        }

        @keyframes gateOpen {
            0%, 100% { opacity: 0.5; }
            50% { opacity: 1; }
        }

        .gate-active {
            animation: gateOpen 2s ease-in-out infinite;
        }

        @keyframes ganLoop {
            0% { stroke-dashoffset: 80; }
            100% { stroke-dashoffset: 0; }
        }

        .gan-loop-line {
            stroke-dasharray: 6, 4;
            animation: ganLoop 1.5s linear infinite;
        }

        @keyframes qkvHighlight {
            0%, 100% { fill-opacity: 0.6; }
            50% { fill-opacity: 1; }
        }

        .qkv-highlight {
            animation: qkvHighlight 2s ease-in-out infinite;
        }

        @keyframes attnHeat {
            0%, 100% { opacity: 0.4; }
            50% { opacity: 0.9; }
        }

        .attn-heat {
            animation: attnHeat 1.5s ease-in-out infinite;
        }

        @keyframes residualPulse {
            0%, 100% { stroke-dashoffset: 0; }
            50% { stroke-dashoffset: 10; }
        }

        .residual-line {
            stroke-dasharray: 8, 4;
            animation: residualPulse 1s linear infinite;
        }

        @keyframes skipBounce {
            0%, 100% { transform: translateY(0); }
            50% { transform: translateY(-3px); }
        }

        .skip-bounce {
            animation: skipBounce 1.5s ease-in-out infinite;
        }

        @keyframes signalPulse {
            0% { r: 2; opacity: 0; }
            20% { r: 5; opacity: 1; }
            80% { r: 5; opacity: 1; }
            100% { r: 2; opacity: 0; }
        }

        .nn-signal {
            animation: signalPulse 2s ease-in-out infinite;
        }

        .nn-node {
            transition: all 0.3s ease;
        }

        .nn-node:hover {
            filter: brightness(1.2);
        }

        @keyframes weightFlow {
            0% { stroke-dashoffset: 0; }
            100% { stroke-dashoffset: 20; }
        }

        .nn-weight-line {
            stroke-dasharray: 4, 4;
            animation: weightFlow 1s linear infinite;
        }

        @keyframes fadeInUp {
            from { opacity: 0; transform: translateY(10px); }
            to { opacity: 1; transform: translateY(0); }
        }

        .fade-in-up {
            animation: fadeInUp 0.6s ease-out both;
        }

        /* ==========================================
           AI 边界：能力卡片
           ========================================== */
        .boundary-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: var(--space-lg);
            margin-bottom: var(--space-lg);
        }

        .boundary-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: var(--space-lg);
            transition: all var(--transition-slow);
            box-shadow: var(--shadow-sm);
        }

        .boundary-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .boundary-card.can { border-top: 3px solid #10B981; }
        .boundary-card.cant { border-top: 3px solid #EF4444; }
        .boundary-card.maybe { border-top: 3px solid #F59E0B; }

        .boundary-card:hover.can { border-color: rgba(16, 185, 129, 0.3); }
        .boundary-card:hover.cant { border-color: rgba(239, 68, 68, 0.3); }
        .boundary-card:hover.maybe { border-color: rgba(245, 158, 11, 0.3); }

        .boundary-card h4 {
            font-family: 'Noto Serif SC', serif;
            font-size: 1rem;
            color: var(--text-primary);
            margin-bottom: var(--space-sm);
        }

        .boundary-card p {
            color: var(--text-secondary);
            font-size: 0.85rem;
            line-height: 1.65;
        }