/* 页面背景 */
    body { background-color: #f5f8fb; }

    /* 1. 顶部 Banner */
    .down-banner {
        background: linear-gradient(135deg, #0066ff 0%, #00c6ff 100%);
        padding: 150px 0 100px;
        color: #fff;
        text-align: center;
        margin-bottom: 0;
    }

    /* 2. 选项卡导航 (5个方块) */
    .nav-box-container {
        margin-top: -50px; /* 往上提，压住Banner */
        margin-bottom: 40px;
        position: relative;
        z-index: 10;
    }
    .nav-box-row {
        display: flex;
        justify-content: center;
        gap: 15px;
        flex-wrap: wrap;
    }
    .nav-item-static {
        width: 200px; /* 固定宽度 */
        background: #fff;
        border-radius: 12px;
        text-align: center;
        padding: 25px 10px;
        cursor: pointer;
        border: 2px solid #eee;
        transition: 0.3s;
        box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    }
    /* 图标圈 */
    .nav-icon-circle {
        width: 50px; height: 50px;
        background: #f8f8f8;
        border-radius: 50%;
        margin: 0 auto 10px;
        display: flex; align-items: center; justify-content: center;
        font-size: 24px; color: #666;
    }
    .nav-item-static h4 { font-size: 16px; font-weight: bold; margin-bottom: 5px; color: #333; }
    .nav-item-static p { font-size: 12px; color: #999; margin: 0; }

    /* 选中状态 */
    .nav-item-static.active {
        border-color: #0066ff;
        background-color: #f0f7ff;
    }
    .nav-item-static.active .nav-icon-circle {
        background-color: #fff; color: #0066ff;
    }

    /* 3. 软件卡片 */
    .soft-card-static {
        background: #fff;
        border-radius: 12px;
        padding: 25px;
        margin-bottom: 25px;
        border: 1px solid #eee;
        transition: 0.3s;
        height: 100%;
        display: flex;
        flex-direction: column;
    }
    .soft-card-static:hover {
        transform: translateY(-5px);
        box-shadow: 0 10px 30px rgba(0,0,0,0.08);
    }
    .card-head { display: flex; margin-bottom: 20px; }
    .card-icon { width: 60px; height: 60px; margin-right: 15px; flex-shrink: 0; }
    .card-icon img { width: 100%; height: 100%; object-fit: contain; }
    
    .card-info h5 { font-weight: bold; font-size: 18px; margin-bottom: 5px; color: #333; }
    .card-meta { font-size: 12px; color: #888; display: flex; gap: 10px; }
    
    .card-desc {
        font-size: 13px; color: #666; line-height: 1.6;
        margin-bottom: 20px; flex-grow: 1;
        overflow: hidden; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical;
    }
    
    .card-btns { display: flex; gap: 10px; margin-top: auto; }
    .btn-static {
        flex: 1; padding: 8px 0; border-radius: 6px; font-size: 14px; text-align: center;
        text-decoration: none; display: inline-block;
    }
    .btn-outline { background: #eef5ff; color: #0066ff; }
    .btn-solid { background: #0066ff; color: #fff; }
    .btn-solid:hover { background: #0052cc; color: #fff; }

    /* 隐藏辅助类 */
    .hidden-card { display: none !important; }
    
    /* 手机端适配 */
    @media (max-width: 768px) {
        .nav-item-static { width: 45%; min-width: auto; }
    }