/* ============================================================
   纸飞机 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 { font-family: "Microsoft YaHei", "PingFang SC", sans-serif; background: #ffffff; color: #1e1e2a; line-height: 1.6; }
        .container { max-width: 1140px; margin: 0 auto; padding: 0 20px; }
        a { text-decoration: none; transition: 0.25s; }
        h2 { font-size: 30px; font-weight: 700; color: #1e1e2a; margin-bottom: 30px; text-align: center; letter-spacing: -0.3px; }
        h3, h4 { font-weight: 600; color: #1e1e2a; }

        /* 导航 */
        .header { background: #ffffff; padding: 14px 0; border-bottom: 1px solid #f0f0f5; position: sticky; top: 0; z-index: 100; }
        .nav-flex { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; }
        .logo { display: flex; align-items: center; font-size: 22px; font-weight: 700; color: #0088cb; }
        .logo img { width: 28px; margin-right: 10px; }
        .nav-list { display: flex; list-style: none; gap: 28px; }
        .nav-list a { color: #36324a; font-weight: 500; font-size: 15px; }
        .nav-list a:hover { color: #0088cb; }
        .nav-list a.active { color: #0088cb; }

        /* 下载区域 (左图右文) */
        .download-wrapper { padding: 70px 0 60px; background: #fafafc; border-bottom: 1px solid #f0f0f5; }
        .download-flex { display: flex; align-items: center; gap: 60px; flex-wrap: wrap; }
        .download-media { flex: 1.2; min-width: 300px; text-align: center; }
        .download-media img { width: 80%; max-width: 380px; border-radius: 20px; box-shadow: 0 12px 30px rgba(0,0,0,0.08); }
        .download-content { flex: 1; min-width: 300px; }
        .download-content h1 { font-size: 36px; color: #1e1e2a; margin: 0 0 16px; line-height: 1.2; }
        .download-content p { font-size: 16px; color: #4c4f60; margin-bottom: 30px; }
        .btn-group-vertical { display: flex; flex-direction: column; gap: 12px; max-width: 380px; }
        .btn-dl { 
            display: inline-flex; align-items: center; justify-content: center; 
            padding: 16px 32px; background: #0088cb; color: #fff !important; 
            border-radius: 60px; font-weight: 600; font-size: 18px; gap: 12px;
            transition: 0.25s; border: none; cursor: pointer;
        }
        .btn-dl:hover { background: #1a2a3a; transform: scale(1.02); box-shadow: 0 8px 24px rgba(0,136,203,0.3); }
        .btn-dl img { width: 28px; height: 28px; filter: brightness(0) invert(1); }
        .sys-info { font-size: 13px; color: #999; display: block; text-align: center; margin-top: 6px; }

        /* ===== 新：6步安装教程 (替换原feature-section) ===== */
        .tutorial-section { padding: 70px 0; background: #ffffff; }
        .tutorial-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; margin-top: 10px; }
        .tutorial-step { 
            background: #f8f9fc; border-radius: 20px; padding: 30px 24px; 
            display: flex; flex-direction: column; align-items: flex-start;
            transition: 0.2s; border-left: 4px solid #0088cb;
        }
        .tutorial-step:hover { background: #f0f4f9; transform: translateY(-3px); }
        .tutorial-step .step-num { 
            display: inline-flex; align-items: center; justify-content: center;
            background: #0088cb; color: #fff; font-weight: 700; 
            width: 36px; height: 36px; border-radius: 50%; font-size: 18px; 
            margin-bottom: 16px; flex-shrink: 0;
        }
        .tutorial-step h3 { font-size: 20px; margin-bottom: 8px; }
        .tutorial-step p { color: #4c4f60; font-size: 15px; margin: 0; line-height: 1.7; }
        .tutorial-step .badge { 
            margin-top: 14px; display: inline-block; 
            background: #e6f0f8; color: #0088cb; 
            border-radius: 30px; padding: 4px 16px; font-size: 13px; font-weight: 500;
        }

        /* info-section (保留原有风格) */
        .info-section { padding: 70px 0; background: #f7f8fc; }
        .info-flex { display: flex; gap: 50px; flex-wrap: wrap; }
        .info-column { flex: 1; min-width: 280px; }
        .info-column h2 { text-align: left; font-size: 26px; border-left: 5px solid #0088cb; padding-left: 16px; margin-bottom: 30px; }
        .step-list { padding: 0; list-style: none; }
        .step-item { display: flex; gap: 20px; margin-bottom: 25px; }
        .step-num { background: #0088cb; color: #fff; width: 32px; height: 32px; border-radius: 50%; display: flex; align-items: center; justify-content: center; flex-shrink: 0; font-weight: 700; font-size: 15px; }
        .step-text h4 { margin: 0 0 6px; font-size: 17px; }
        .step-text p { margin: 0; font-size: 14px; color: #4c4f60; }
        .faq-item { margin-bottom: 24px; }
        .faq-item h4 { font-size: 17px; margin-bottom: 6px; }
        .faq-item p { font-size: 14px; color: #4c4f60; margin: 0; }

        /* footer */
        footer { text-align: center; padding: 40px 0 30px; color: #999; font-size: 14px; border-top: 1px solid #f0f0f5; background: #fff; }
        footer .footer-links { display: flex; justify-content: center; gap: 28px; flex-wrap: wrap; margin-top: 12px; }
        footer .footer-links a { color: #6f6c7f; font-size: 14px; }
        footer .footer-links a:hover { color: #0088cb; }

        /* 响应式 */
        @media (max-width: 992px) {
            .tutorial-grid { grid-template-columns: repeat(2, 1fr); }
            .download-flex { flex-direction: column; text-align: center; }
            .btn-group-vertical { margin: 0 auto; }
        }
        @media (max-width: 700px) {
            .tutorial-grid { grid-template-columns: 1fr; }
            .nav-list { display: none; }
            .download-wrapper { padding: 40px 0; }
            .tutorial-section { padding: 40px 0; }
            .info-section { padding: 40px 0; }
        }