/* --- FirstFiber 科技蓝 UI 变量体系 --- */
    .ff-p-center {
        --ff-dark: #0f172a;         /* 工业深蓝 */
        --ff-brand: #0284c7;        /* FirstFiber 科技蓝 */
        --ff-brand-hover: #0369a1;  /* 悬停深蓝 */
        --ff-accent: #f97316;       /* 橙色点缀 */
        --ff-text: #334155;         /* 正文灰 */
        --ff-text-light: #64748b;   /* 次要标注灰 */
        --ff-border: #cbd5e1;       /* 工业级稳固边框 */
        --ff-bg-card: #ffffff;      /* 卡片白 */
        
        font-family: "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
        color: var(--ff-text);
        line-height: 1.5;
        max-width: 1200px;
        margin: 20px auto;
        padding: 0 15px;
    }

    /* --- 工业级头部横幅 --- */
    .ff-banner {
        background: linear-gradient(135deg, #0f172a 0%, #1e3a8a 100%);
        color: #ffffff;
        padding: 40px 30px;
        border-radius: 6px;
        margin-bottom: 30px;
        border-left: 5px solid var(--ff-accent);
    }
    .ff-banner h1 {
        font-size: 1.8rem;
        font-weight: 700;
        margin-bottom: 12px;
        color: #ffffff;
    }
    .ff-banner p {
        color: #94a3b8;
        font-size: 0.95rem;
        max-width: 900px;
    }

    /* --- 产品大类锚点导航 --- */
    .ff-tabs {
        display: flex;
        flex-wrap: wrap;
        gap: 8px;
        margin-bottom: 35px;
        border-bottom: 1px solid #e2e8f0;
        padding-bottom: 12px;
    }
    .ff-tab-btn {
        background: #ffffff;
        border: 1px solid #e2e8f0;
        color: var(--ff-text);
        padding: 6px 16px;
        border-radius: 4px;
        text-decoration: none;
        font-size: 0.9rem;
        font-weight: 500;
        transition: all 0.15s ease;
    }
    .ff-tab-btn:hover {
        border-color: var(--ff-brand);
        color: var(--ff-brand);
        background: #f0f9ff;
    }

    /* --- 产品大类区块 --- */
    .ff-sect {
        margin-bottom: 50px;
        scroll-margin-top: 30px;
    }
    .ff-sect-title {
        font-size: 1.3rem;
        font-weight: 700;
        margin-bottom: 20px;
        color: var(--ff-dark);
        display: flex;
        align-items: center;
        gap: 8px;
    }
    .ff-sect-title::before {
        content: "";
        display: inline-block;
        width: 4px;
        height: 18px;
        background-color: var(--ff-brand);
        border-radius: 2px;
    }

    /* --- 产品响应式网格布局 --- */
    .ff-p-grid {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(360px, 1fr));
        gap: 20px;
    }

    /* --- 核心：单一产品聚合卡片 --- */
    .ff-p-card {
        background: var(--ff-bg-card);
        border: 1px solid var(--ff-border);
        border-radius: 6px;
        padding: 22px;
        display: flex;
        flex-direction: column;
        justify-content: space-between;
        box-shadow: 0 1px 3px rgba(0,0,0,0.05);
        transition: all 0.2s ease;
    }
    .ff-p-card:hover {
        border-color: var(--ff-brand);
        box-shadow: 0 6px 16px rgba(15, 23, 42, 0.08);
    }

    /* 产品型号与名称（SEO 绝对主战区） */
    .ff-p-title {
        font-size: 1.1rem;
        font-weight: 700;
        color: var(--ff-dark);
        margin-bottom: 8px;
        line-height: 1.3;
    }
    
    /* 产品核心技术简述（塞长尾词） */
    .ff-p-desc {
        font-size: 0.85rem;
        color: var(--ff-text-light);
        margin-bottom: 20px;
        line-height: 1.4;
        min-height: 2.8em;
    }

    /* 聚合下载区域（线条隔离） */
    .ff-download-links {
        border-top: 1px dashed #e2e8f0;
        padding-top: 15px;
        display: flex;
        flex-direction: column;
        gap: 10px;
    }

    /* 单条下载链接样式 */
    .ff-link-item {
        display: flex;
        align-items: center;
        justify-content: space-between;
        text-decoration: none !important;
        padding: 8px 12px;
        background-color: #f8fafc;
        border: 1px solid #e2e8f0;
        border-radius: 4px;
        transition: all 0.1s ease;
    }
    .ff-link-item:hover {
        background-color: #f0f9ff;
        border-color: #bae6fd;
    }

    /* 左侧文件类型文本 */
    .ff-link-left {
        display: flex;
        align-items: center;
        gap: 8px;
        font-size: 0.85rem;
        font-weight: 600;
        color: var(--ff-dark);
    }
    /* 区分不同文件类型的图标微色调 */
    .ff-icon-pdf { color: #ef4444; font-weight: bold; font-size: 0.75rem; }
    .ff-file-name { color: var(--ff-text); font-weight: 500; }

    /* 右侧带下载图标的动作区 */
    .ff-link-right {
        display: flex;
        align-items: center;
        gap: 6px;
        font-size: 0.8rem;
        color: var(--ff-brand);
        font-weight: 600;
    }
    .ff-link-item:hover .ff-link-right {
        color: var(--ff-brand-hover);
    }
    .ff-link-right svg {
        width: 14px;
        height: 14px;
        fill: currentColor;
    }

    /* 手机端适配 */
    @media (max-width: 640px) {
        .ff-banner { padding: 25px 20px; }
        .ff-banner h1 { font-size: 1.4rem; }
        .ff-p-grid { grid-template-columns: 1fr; }
    }