/* ============================================================
  快连 Windows 下载页面 - 独立样式表
   文件: css/style.css
   说明: 包含全局变量、布局、下载区、步骤、FAQ 及响应式
   ============================================================ */

/* ---------- 全局变量 ---------- */
 * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        body {
            background-color: #ffffff;
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
            color: #1a1a2e;
            line-height: 1.6;
        }

        .container {
            max-width: 1100px;
            margin: 0 auto;
            padding: 0 24px;
        }

        /* ===== 导航 ===== */
        .navbar {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 18px 0;
            border-bottom: 1px solid #f0f0f0;
            flex-wrap: wrap;
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 10px;
            font-size: 1.6rem;
            font-weight: 700;
            color: #0b0b1a;
            text-decoration: none;
        }
        .logo img {
            height: 36px;
            width: auto;
            display: block;
        }
        .logo span {
            font-weight: 300;
            color: #6b6b7a;
        }

        .nav-links {
            display: flex;
            gap: 30px;
            font-weight: 500;
        }
        .nav-links a {
            text-decoration: none;
            color: #2d2d3a;
            transition: 0.2s;
            font-size: 0.95rem;
        }
        .nav-links a:hover {
            color: #2563eb;
        }

        /* ===== 页面标题 ===== */
        .page-header {
            padding: 50px 0 30px 0;
            text-align: center;
        }
        .page-header h1 {
            font-size: 3rem;
            font-weight: 700;
            letter-spacing: -1px;
            margin-bottom: 10px;
        }
        .page-header h1 i {
            color: #2563eb;
            margin-right: 12px;
        }
        .page-header p {
            font-size: 1.15rem;
            color: #5a5a6e;
            max-width: 550px;
            margin: 0 auto;
        }

        /* ===== Windows 下载卡片 (大) ===== */
        .windows-download-card {
            background: linear-gradient(145deg, #f8faff, #eef2f9);
            border-radius: 40px;
            padding: 50px 50px 45px;
            border: 1px solid #e4e8f0;
            margin: 30px 0 50px 0;
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: space-between;
            gap: 30px;
        }

        .windows-info {
            flex: 1 1 300px;
        }
        .windows-info .badge {
            display: inline-block;
            background: #2563eb;
            color: #fff;
            padding: 4px 18px;
            border-radius: 40px;
            font-size: 0.75rem;
            font-weight: 600;
            letter-spacing: 0.5px;
            text-transform: uppercase;
            margin-bottom: 12px;
        }
        .windows-info h2 {
            font-size: 2.2rem;
            font-weight: 700;
            margin-bottom: 8px;
        }
        .windows-info .version {
            color: #5a5a6e;
            font-size: 0.95rem;
            margin-bottom: 16px;
        }
        .windows-info .desc {
            color: #3a3a4e;
            font-size: 1rem;
            max-width: 400px;
        }
        .windows-info .desc i {
            color: #2563eb;
            margin-right: 6px;
            width: 20px;
        }

        .windows-download-btn {
            flex-shrink: 0;
        }

        /* ===== 按钮 (完全按要求) ===== */
        .btn {
            background: #0b1e33;
            border: none;
            border-radius: 48px;
            padding: 16px 40px;
            font-size: 1.15rem;
            font-weight: 600;
            color: white;
            display: inline-flex;
            align-items: center;
            gap: 14px;
            box-shadow: 0 8px 28px rgba(0, 20, 80, 0.15);
            transition: 0.25s ease;
            cursor: pointer;
            border: 1px solid rgba(255,255,255,0.06);
        }
        .btn i {
            font-size: 1.4rem;
            color: #8bb3ff;
        }
        .btn:hover {
            background: #112f4b;
            transform: scale(1.03);
            box-shadow: 0 12px 32px rgba(0, 30, 90, 0.25);
        }
        .btn:active {
            transform: scale(0.97);
        }

        .btn-secondary {
            background: #eef2f9;
            color: #0b1e33;
            box-shadow: none;
        }
        .btn-secondary i {
            color: #2563eb;
        }
        .btn-secondary:hover {
            background: #e4e8f2;
            box-shadow: 0 4px 16px rgba(0,0,0,0.06);
        }

        /* ===== 系统要求 ===== */
        .requirements {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
            gap: 20px;
            margin: 40px 0 50px 0;
        }
        .req-item {
            background: #f8faff;
            border-radius: 20px;
            padding: 20px 22px;
            border: 1px solid #eef2f8;
            text-align: center;
        }
        .req-item i {
            font-size: 1.8rem;
            color: #2563eb;
            margin-bottom: 6px;
        }
        .req-item h4 {
            font-size: 0.95rem;
            font-weight: 600;
        }
        .req-item p {
            font-size: 0.85rem;
            color: #6a6a7e;
        }

        /* ===== 安装步骤 (网格2列) ===== */
        .section-title {
            font-size: 2rem;
            font-weight: 700;
            margin: 50px 0 30px 0;
            display: flex;
            align-items: center;
            gap: 12px;
        }
        .section-title i {
            color: #2563eb;
        }

        .steps-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 24px;
        }

        .step-card {
            background: #f8faff;
            border-radius: 24px;
            padding: 24px 26px;
            border: 1px solid #eef2f8;
            display: flex;
            gap: 16px;
            align-items: flex-start;
            transition: 0.2s;
        }
        .step-card:hover {
            background: #f4f8ff;
            border-color: #d0ddea;
            transform: translateY(-3px);
        }
        .step-num {
            background: #0b1e33;
            color: #fff;
            width: 38px;
            height: 38px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 1rem;
            flex-shrink: 0;
        }
        .step-content h4 {
            font-size: 1.05rem;
            font-weight: 600;
            margin-bottom: 2px;
        }
        .step-content p {
            font-size: 0.92rem;
            color: #5a5a6e;
        }

        /* ===== 使用教程 (网格2列) ===== */
        .tutorial-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 24px;
            margin-bottom: 60px;
        }

        .tutorial-card {
            background: #ffffff;
            border-radius: 24px;
            padding: 26px 26px;
            border: 1px solid #eef2f8;
            transition: 0.2s;
        }
        .tutorial-card:hover {
            background: #f8faff;
            border-color: #c8d7ed;
            transform: translateY(-3px);
        }
        .tutorial-card .tut-icon {
            font-size: 2rem;
            color: #2563eb;
            margin-bottom: 8px;
        }
        .tutorial-card h4 {
            font-size: 1.15rem;
            font-weight: 600;
            margin-bottom: 8px;
        }
        .tutorial-card ol {
            padding-left: 18px;
            font-size: 0.92rem;
            color: #4a4a5e;
            line-height: 1.8;
        }

        /* ===== 其他版本 ===== */
        .other-versions {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 20px;
            margin: 30px 0 50px 0;
        }
        .other-version-item {
            background: #f8faff;
            border-radius: 20px;
            padding: 20px;
            text-align: center;
            border: 1px solid #eef2f8;
            transition: 0.2s;
            text-decoration: none;
            color: #1a1a2e;
        }
        .other-version-item:hover {
            background: #f0f5ff;
            border-color: #2563eb;
            transform: translateY(-3px);
        }
        .other-version-item i {
            font-size: 2rem;
            color: #2563eb;
            margin-bottom: 6px;
        }
        .other-version-item h4 {
            font-size: 1rem;
            font-weight: 600;
        }
        .other-version-item p {
            font-size: 0.8rem;
            color: #6a6a7e;
        }

        /* ===== 页脚 ===== */
        .footer {
            background: #f8faff;
            padding: 28px 0;
            border-top: 1px solid #eef0f5;
            margin-top: 20px;
        }
        .footer .container {
            display: flex;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 12px;
            font-size: 0.9rem;
            color: #4a4a5e;
        }
        .footer a {
            color: #4a4a5e;
            text-decoration: none;
        }
        .footer a:hover {
            color: #2563eb;
        }
        .footer .links {
            display: flex;
            gap: 24px;
        }

        /* ===== 响应式 ===== */
        @media (max-width: 992px) {
            .steps-grid,
            .tutorial-grid {
                grid-template-columns: 1fr 1fr;
            }
            .other-versions {
                grid-template-columns: 1fr 1fr;
            }
        }

        @media (max-width: 768px) {
            .container {
                padding: 0 18px;
            }
            .navbar {
                flex-direction: column;
                align-items: flex-start;
                gap: 12px;
            }
            .nav-links {
                flex-wrap: wrap;
                gap: 16px;
            }
            .page-header h1 {
                font-size: 2.2rem;
            }
            .windows-download-card {
                padding: 30px 24px;
                flex-direction: column;
                text-align: center;
            }
            .windows-info .desc {
                max-width: 100%;
            }
            .windows-download-btn {
                width: 100%;
            }
            .windows-download-btn .btn {
                width: 100%;
                justify-content: center;
            }
            .steps-grid,
            .tutorial-grid {
                grid-template-columns: 1fr;
            }
            .other-versions {
                grid-template-columns: 1fr 1fr;
            }
            .section-title {
                font-size: 1.6rem;
            }
            .requirements {
                grid-template-columns: 1fr 1fr;
            }
        }

        @media (max-width: 480px) {
            .page-header h1 {
                font-size: 1.8rem;
            }
            .windows-info h2 {
                font-size: 1.6rem;
            }
            .windows-download-card {
                padding: 24px 16px;
            }
            .btn {
                padding: 14px 24px;
                font-size: 1rem;
                gap: 10px;
            }
            .btn i {
                font-size: 1.2rem;
            }
            .other-versions {
                grid-template-columns: 1fr 1fr;
                gap: 12px;
            }
            .requirements {
                grid-template-columns: 1fr;
            }
            .step-card {
                padding: 18px 16px;
            }
            .tutorial-card {
                padding: 18px 16px;
            }
            .footer .container {
                flex-direction: column;
                align-items: center;
                text-align: center;
            }
            .footer .links {
                flex-wrap: wrap;
                justify-content: center;
            }
        }